The United States will end the 1972 Anti-Ballistic Missile treaty with Russia when it concludes that its restrictions on missile defense are blocking U.S. innovation, Secretary of State Colin Powell said on Fox News Sunday.

But that point has not been reached, he said, as the Bush administration searches for a shield against missile attacks in the post-Cold War era.

Powell also said Russian President Vladimir Putin wants to continue discussions about missile defense aspirations. "There may be opportunities to move forward," Powell said a day after Bush's inaugural meeting with Putin, in Slovenia.

The first talks between the two leaders, which focused on NATO expansion and missile defense, also served as a "getting to know you" session and bridged the gap for future meetings in Italy, Russia and Bush's ranch in Texas.

The talks were the culmination of Bush's five-day European tour.

Putin has restated his opposition to a national missile defense program, which is outlawed by the treaty signed by the United States and the Soviet Union.

But Powell said the treaty was reached in a different era. "We cannot allow its constraints" to bind American technology, he said.

The agreement is "designed to keep us from moving in this direction" of a missile defense system, Powell said on ABC's This Week.

"If there is no ABM treaty tomorrow, there is no nation that's going to run out and start making nuclear weapons," he said, adding that the United States has made it clear that "we are going to go forward with missile defense."

Powell also said the U.S. and Russia would hold talks on "tracking down" Russian companies and scientists who are assisting Iran develop weapons.

"Russia should see it is more in their interest than ours" to stop weapons proliferation, Powell said.

He encouraged the expansion of programs designed to give Russian scientists an incentive to remain at home. "We can do more," Powell said, without providing any details.

"We have to keep talking to them about this to make sure we are of a unified mind," he said.

The Associated Press contributed to this report