"The biggest problem we have in doping and cycling comes from Spain," UCI president Pat McQuaid said in an interview with The Associated Press. "There seems to be a reluctance to completely clean the problem out in Spain."

Speaking two days before the start of the world championships in Stuttgart, McQuaid accused the Spanish cycling federation of being soft on doping and criticized the government for not following up new laws with tough action.

On Wednesday, the International Cycling Union and the Spanish federation will argue before the Court of Arbitration for Sport over whether Spanish cyclist Alejando Valverde can compete in Sunday's road race.

The UCI had asked the Spanish federation to open disciplinary proceedings against Valverde after discovering new evidence in a 6,000-page Operation Puerto file linking him to the Spanish doping scandal. The Spanish federation said it also reviewed the document but found no new evidence.

McQuaid was especially upset that Spanish Sports Minister Jaime Lissavetsky sided with the Spanish cycling federation, which wants Valverde on the team. The UCI wants to keep him out.

McQuaid said the minister's position was "indicative" of Spain's position on doping, despite a new anti-doping law.

"It is all very well bringing in laws, but you need to bring action after that," he said.

The Sports Ministry said it wouldn't respond to McQuaid's comments until it sees them.

The UCI monitors riders' blood values, and McQuaid said those from Spanish riders stood out.

"The evidence we have from blood values from riders that we take indicates to us that there is manipulation of blood going on in Spain," he said. "And it is more so than in any other country.

"That shows to me that the authorities are not coming down strong enough. The culture change which is being effected throughout the rest of Europe is not being effected in Spain."

Asked what Spain could do, McQuaid said there should be more controls on riders and a major crackdown on suppliers.

He also derided the slow pace of Operation Puerto, which broke in May 2006 when Spanish authorities seized about 100 bags of frozen blood in the Madrid offices of doctor Eufemiano Fuentes.

On the eve of the 2006 Tour de France, nine riders — including 1997 champion Jan Ullrich and 2005 runner-up Ivan Basso — were excluded after being implicated in the scandal. The investigation implicated 58 cyclists, but a judge threw out the case.

The UCI, however, has continued to pursue the matter.