Alberto Contador said on Friday he will quit the Astana cycling team if his leadership is put in doubt by the arrival of seven-time Tour de France champion Lance Armstrong.

Armstrong announced on Wednesday he was joining Astana, reuniting him with his friend Johan Bruyneel after three years in retirement. Now Astana's team director, Bruyneel coached Armstrong during his Tour victories.

"I spoke with Johan about the Tour next year and he said there is no problem and that I will be the leader, but Lance Armstrong is a champion and I think he will want to race to win," Contador, 25, told The Associated Press in an interview. "I am sure that he also wants to be the leader of the team."

Contador, winner of the 2007 Tour de France, said he has received offers to sign with other cycling teams, though he is not considering them right now.

"If I am not happy I will change teams," the Spaniard said. "The team has said it has complete confidence in me, but this is a particular situation and I will have to see what happens in the coming weeks to then decide what is best for my future. Four weeks from now the situation could be completely different."

Contador, who is under contract with Astana until 2010, said his main objective for next year's season is the Tour de France. That could put him on a collision course with Armstrong, who also plans to race in the Tour in a bid for an eighth victory.

"I respect Armstrong. He has done incredible things, but I don't think that I have to prove to anybody that I should be the leader," said Contador, who is in Italy preparing for Sunday's road race at the World Championships. "I want to be sure the team guarantees that I will be in the Tour as the team leader."

The Madrid-born rider won the Spanish Vuelta this month, completing the fastest sweep of the three major multi-day races. Contador has won the Vuelta, the Tour and the Giro d'Italia in 15 months. On Sunday, he will be riding in support of team-mates Oscar Freire and Samuel Sanchez, who are among the pre-race favorites.

Armstrong was an inspirational figure for Contador while the Spaniard was recovering form a massive blood clot in his brain in 2004.

Contador has said that while recovering from surgery, he drew hope from Armstrong's book recounting his comeback from cancer.

"When I was recovering it was important for me to see that somebody could make a comeback like Armstrong did," Contador said. "At the time it was easy to have him as an idol because we were from different eras and I didn't have to ride against him. When I was finishing my recovery he was winning his last Tour, but now these eras are colliding and it's not so easy."

AFP