LONDON — Police in London's bustling nightclub and theater district on Friday defused a car bomb that could have killed hundreds after an ambulance crew spotted smoke coming from a Mercedes filled with a lethal mix of gasoline, propane and nails. Hours later, police confirmed a second explosives-rigged car was found nearby.

The first car bomb, found near Piccadilly Circus, was powerful enough to have caused "significant injury or loss of life" at a time when hundreds were in the area, British anti-terror police chief Peter Clarke said.

Clarke said Friday evening that the second car — another Mercedes — was originally parked illegally on nearby Cockspur Street, but had been towed from the West End to an impound lot near Hyde Park.

"The vehicle was found to contain very similar materials to those that had been found in the first car," he said. "There was a considerable amount of fuel and gas canisters. As in the first vehicle, there was also a quantity of nails. This like the first device was potentially viable."

The discoveries came just ahead of the second anniversary of the July 7, 2005, suicide bombings that killed 52 people on three London subways and a bus, and two days after Gordon Brown became Britain's prime minister.

U.S. URGES VIGILANCE FOLLOWING LONDON THREAT

WASHINGTON — Unexploded car bombs in London led to extra patrols in the United States Friday, but Bush administration officials said they saw no special terrorist threat heading toward next week's Fourth of July holiday.

Homeland Security Secretary Michael Chertoff urged Americans to be vigilant but said there were no immediate plans to raise the U.S. national threat level, now at yellow, or elevated.

Said White House press secretary Tony Snow: "There is no specific or credible evidence of any threat of any kind against the United States of America." He was in Kennebunkport, Maine, where President Bush will meet Sunday with Russian President Vladimir Putin.

Snow said British authorities had not yet been able to determine if there was a link to any terrorist group.

"Look, it's terrorism, but we don't know if there — there's no definite, there's no established connection with any organization at this point," he said. Snow said U.S. officials "remain very aggressively engaged" with the British.

AMBUSH CAPS BLOODIEST 3-MONTHS IN IRAQ

BAGHDAD — A huge bomb explosion followed by a hail of gunfire and grenades killed five U.S. soldiers, the military said Friday. The attack came as the Pentagon tallied up the deadliest three-month period for Americans since the war began.

Seven soldiers were wounded in the attack Thursday in the Rasheed district, a mixed Sunni-Shiite area of southern Baghdad where U.S.-led forces recently stepped up pressure on extremists. The commander of U.S. forces in Baghdad suggested the ambush could be part of an escalating backlash by Sunni insurgents.

Those deaths brought to 99 the number of U.S. troops killed this month, according to an Associated Press count. The toll for the past three months — 329 — made it the deadliest quarter for U.S. troops in Iraq since the March 2003 invasion. That surpasses the 316 soldiers killed during November 2004 to January 2005.

Maj. Gen. Joseph F. Fil Jr., who heads U.S. forces in the Iraqi capital, said U.S. casualties had mounted because Sunni extremists are "starting to fight very hard" as U.S. forces press into areas of the capital where militants once had free rein.

"This is a skilled and determined enemy. He's ruthless. He's got a thirst for blood like I've never seen anywhere in my life," Fil told reporters. "And he's determined to do whatever he can."

DEMOCRATS WANT EXPLANATION OF EXECUTIVE PRIVILEGE

WASHINGTON — Democrats took the first steps Friday in what could be a long march to court in a tug-of-war between the White House and Congress over subpoenas and executive and legislative branch powers.

In a letter to White House counsel Fred Fielding, the heads of the Senate and House Judiciary committees demanded an explanation in 10 days of why the White House claimed executive privilege on subpoenaed documents and vowed to invoke "the full force of law."

The White House — echoing the senior Republican on the Senate panel — urged the chairmen to accept the administration's earlier offer to allow private, off-the-record interviews with current and former aides to President Bush.

"If the committees just want the facts, then they should withdraw the subpoenas and accept the president's offer, instead of this continued pattern of gross overreach and confrontation," said White House spokesman Tony Fratto.

The fight centers on an investigation that Democrats initially undertook into the firings of several U.S. attorneys, but which has since branched out to scrutiny of the administration's terrorism-era warrantless wiretapping and Attorney General Alberto Gonzales' stewardship of the Justice Department.

DEMOCRATS HOPE TO CLOSE GUANTANAMO

WASHINGTON — House Democrats want to cut President Bush's budget for Guantanamo Bay prison in half, beating the administration to the punch in shutting down the facility for terror detainees.

The White House says Bush has already decided to close the U.S. prison in Cuba and transfer more than 370 terrorism suspects elsewhere, possibly including the maximum-security military prison in Fort Leavenworth, Kan.

The prison, which began housing terror suspects five years ago, has become a focus for criticism of the Bush administration at home and abroad. Only a few detainees have been selected for trial, leaving the majority in legal limbo and barred from protesting their detentions in court.

With no timetable announced by Bush, Congress is moving ahead on its own. In July, the House Appropriations Committee is expected to propose funding only half of Guantanamo's budget in the military's annual spending bill.

While a precise figure of how much would be cut was not immediately available, the prison's annual operation budget is about $125 million a year.

Acting before Bush is ready would enable Democrats to claim victory in closing the prison.

RAIN CONTINUES TO PELT TEXAS, OKLAHOMA

More rain falling in Texas and Oklahoma; flood watches posted and evacuations under way

FORT WORTH, Texas — Flood-weary residents of Texas and Oklahoma had no reprieve Friday as more rain fell in a region where two weeks of storms have swollen rivers and lakes beyond their limits.

Thousands of people have been forced from their homes, though some residents were holding out, saying conditions are no worse than floods they've weathered before.

A state of emergency was in place for all of Oklahoma on Friday, and flood watches and warnings were posted for river communities. A flood watch was in effect for large portions of Texas, where the storms have been blamed for at least 11 deaths.

The rains had tapered off and become more isolated, but National Weather Service meteorologist Greg Patrick said storms could cluster and create a more widespread threat of flooding by the weekend.

"The storms are very efficient rain producers, and if you happen to be under one of them you can pick up 1› or 2 inches an hour," said another meteorologist, Jesse Moore. "Right now with the ground being saturated, it's all run-off and that causes the flash flooding we've been seeing."

BENOIT'S DAD: TOX TESTS MAY HOLD ANSWERS

ATLANTA — The father of pro wrestler Chris Benoit said Friday that he was eager to see whether chemical tests can help explain why Benoit killed his wife and son and committed suicide, acts the wrestler's father said he had no clue were coming.

Michael Benoit said by phone from his home in Canada that his family is shocked and in disbelief over the slayings.

"We have no understanding of why it happened," he said. "We need some time to gather our thoughts and wait and see. There's still more information that's going to come out from toxicology tests that will give us some understanding of why this happened."

Anabolic steroids were found in Chris Benoit's home in an Atlanta suburb, leading officials to wonder whether the drugs played a role in the killings, which took place last weekend. Some experts believe steroids can cause paranoia, depression and violent outbursts known as "roid rage."

The wrestler strangled his wife and 7-year-old son, placing Bibles next to their bodies, before hanging himself on the cable of a weight-machine in his home, authorities said. No motive was offered for the killings.

HARRY POTTER GETS FIRST ONSCREEN KISS

TOKYO — First kisses can be tricky. Even for Harry Potter. Daniel Radcliffe, the star of the Harry Potter series, said Friday while in Tokyo for the premiere of the latest installment that it took a few takes to get over the nerves of getting the young wizard through his first on-screen kiss.

And even then, he didn't really feel the magic.

"When we started it, we were both a bit nervous," Radcliffe said at a news conference. "But after the first few takes, it was sort of like any other scene, which is never really what people want to hear. It doesn't really feel any different, because you are still acting."

In "Harry Potter and the Order of the Phoenix," the latest in the megahit series based on J.K. Rowling's books, Harry comes of age and has his first on-screen kiss, with longtime crush Cho Chang, played by Katie Leung.

It was a big moment for Harry — if not for Radcliffe.