WASHINGTON — Determined to change the way the world views the United States, President Obama is on to his next foreign mission: rebuilding relations with Russia, proving to global leaders that America is serious about climate change, and outlining his vision for Africa, his father's birthplace.

And when in Rome? Obama will go to the Vatican to see Pope Benedict XVI for their first meeting.

Obama's weeklong trip — he leaves tonight for Moscow — typifies the pace of his first-year agenda.

Capitalizing on his popularity and his party's hold on power in Washington, Obama is moving quickly and broadly on foreign policy. That often means overturning George W. Bush's policies or mending relations that Obama contends went adrift under his Republican predecessor.

Familiar foes may shadow Obama and his plans.

Iran and North Korea are defiantly pursuing nuclear weapons programs despite international penalties. Iran has taken a hard and deadly line against postelection protesters, while North Korea fired seven ballistic missiles off its eastern coast on America's Independence Day. The North also has raised the prospect of a long-range missile launch, possibly toward Hawai'i. The U.S. has positioned more missile defenses around the state.

Obama's trip is anchored around a yearly meeting of leaders from the world's industrial powers, set for Italy. The Group of Eight countries — the U.S., Japan, Germany, France, Britain, Italy, Canada and Russia — will try to make progress on climate change.

Before the Italy meeting, Obama holds a nuclear-arms-focused summit in the Russian capital. The final leg of the trip brings the first black U.S. president to Africa, home to Obama's late Kenyan-born father.

Obama set a tone for the Moscow meeting by saying in an Associated Press interview Thursday that he was off to a good start with Russian President Dmitry Medvedev. But, Obama added, Vladimir Putin — Medvedev's predecessor and the current prime minister — "still has a lot of sway in Russia."

Obama has separate meetings with them.

"I think Putin has one foot in the old ways of doing business and one foot in the new," Obama said in the interview. Putin responded Friday by poking fun at Obama's imagery and saying the new U.S. president is wrong about him. A Putin spokes-man said Obama would change his mind after meeting Putin.

"Putin knows that, given Medvedev's position, he's the guy who deals with foreign leaders," said Stephen Sestanovich, a Russian expert at the Council on Foreign Relations. "But Putin wants to find ways of reminding everybody who's really in charge. And I don't doubt that he will find ways of doing that."

Obama expects to emerge from Moscow with a framework for how the U.S. and Russia will go about reducing their stockpile of nuclear warheads. He and Medvedev stated their intentions toward that goal in April during a London meeting that had both leaders talking of a fresh start.

Any tangible progress now will be held up as proof of better U.S.-Russia ties, and a step toward broader cooperation on ridding the world of nuclear arms.

Yet there is harder work ahead to determine how many weapons both sides will give up and how those steps will be verified. Both sides hope to have a final deal in place before a current treaty expires in December.

Obama also plans to give a major address on U.S.-Russia relations and meet with a range of civic leaders, hoping to turn around Russian attitudes of the U.S.

"I think that there have been times over the last several years where U.S.-Russian relations were not as strong as they should be," Obama told state-owned Russia TV. "What I have said coming in is I want to press the restart button on relations between the United States and Russia."

In Italy, the G-8 international summit will center on the recession but is expected to produce more of a recovery progress report than new policy. Iran, climate change, food security in Africa, Middle East peace and trade also are on the agenda.

Obama will meet the pope on Friday. The president said he has a policy agenda in mind, including such matters as global poverty, but made clear that "having a meeting with the Holy Father is a great honor, and something that I'm very much looking forward to."

The president caps the trip in Ghana, a West African country that has emerged as a standout example of democracy in a region beset by coups. He will speak to parliament, emphasizing the promise of democratic governance, and tour a castle that once served as a hub of slave trading.