MOSCOW, October 18 (RIA Novosti) - Russian President Vladimir Putin said on Thursday that the U.S.-led invasion of Iraq was mainly aimed at controlling the Gulf state's oil reserves.

During his annual televised question-and-answer session, the president responded to a request for his appraisal of the Iraq war by stating that, "One of the goals, in my opinion, was to establish control over the country's crude reserves."

He also said that the U.S. should fix a date for the withdrawal of its troops from Iraq.

"If the Iraqi authorities know the exact U.S. troop withdrawal date, they will work hard and consistently to enhance the country's own armed forces," Putin said, adding that they would otherwise remain inactive, feeling secure and protected "under the U.S. umbrella".

On the other hand, the president said he agreed with U.S. President George W. Bush that U.S. forces should remain in Iraq as long as their assistance is needed to ensure security.

"The U.S. contingent should only be withdrawn when the Iraqi leadership is capable of maintaining security and stability in the region," Putin said.

He called Iraq "a small country, which holds enormous oil reserves, but is hardly capable of protecting itself."

Putin also said that, "Some hotheads have come up with the idea of getting access to Russian oil reserves, particularly in east Siberia." He did not specify further.

Asked by a Siberian mechanic to comment on a statement, allegedly made several years ago by former U.S. secretary of state Madeleine Albright, to the effect that Siberia had too many natural resources to belong to one country, the president replied that "Russia has sufficient strength and means to protect its interests on its territory and in other regions of the world."