President Bush on Wednesday renewed urgent calls for NATO to start the admission process for Ukraine and Georgia despite a split among alliance members and fierce Russian objections, AP reports.

The president said the two former Soviet states are ready for membership and that NATO leaders at a summit this week must make clear that membership will remain open to all European nations, no matter what Moscow thinks.

"We must make clear that NATO welcomes the aspirations of Georgia and Ukraine for membership in NATO and offers them a clear path forward toward that goal," Bush said in a speech ahead of a summit of alliance leaders in Bucharest.

"So my country`s position is clear: NATO should welcome Georgia and Ukraine into the Membership Action Plan. And NATO membership must remain open to all of Europe`s democracies that seek it, and are ready to share in the responsibilities of NATO membership."

The stance puts him at odds with Russia, which is opposed to the former Soviet republics becoming part of the trans-Atlantic alliance, as well as France and Germany, which fear their entry might alter the balance of power in Europe.

Bush also called for NATO members to step up troop contributions in Afghanistan, citing Osama bin Laden`s latest threats to Europe.

The president says that if the alliance does not stay on the offense in Afghanistan, Taliban and al-Qaida extremists will use the country to launch more attacks on the West like those on Sept. 11, 2001.

"If we were to let up the pressure, the extremists would re-establish safe havens across the country, and use them to terrorize the Afghan people and threaten our own," he said in a speech ahead of a summit of NATO leaders here.

"Just two weeks ago, Osama bin Laden issued an audio recording in which he threatened Europe with new attacks," he said. "We need to take the words of the enemy seriously. The terrorist threat is real, it is deadly, and defeating this enemy must be the top priority of the NATO alliance.