U.S. officials say President Bush will pursue an aggressive strategy to enhance NATO's role at a summit in Prague next week. The summit will shape the new outlook of the trans-atlantic alliance as it expands eastward.

NATO members are expected to grant membership to seven central and eastern European countries at the summit on November 21 and 22-Slovakia, Slovenia, Romania, Bulgaria and the three Baltic states, Lithuania, Estonia and Latvia. Poland, Hungary and the Czech Republic joined in 1999.

U.S. officials say new members benefit from more security but can also contribute in specialized capabilities.

A senior U.S. official who doesn't want to be identified told reporters Thursday that Romania's Red Scorpions combat battalion currently in Afghanistan or Slovenia's expert mountain military units have potential for future NATO missions.

U.S. officials also say they will seek to create a new NATO rapid reaction force. The European Union is seeking to establish a similar force. But U.S. officials say these two forces could be complementary, with the EU force focusing on humanitarian missions while the NATO response force focusses on combat.

The United States will also seek to convince Russia that eastward NATO expansion is also in Russia's interest because it creates a pan-European zone of stability. A Russia NATO council created early this year gives Russia a say in decisions on European security affairs.

Following the summit, President Bush is expected to travel to Russia to meet with Russian President Vladimir Putin in St. Petersburg. The two leaders will discuss NATO's future but also the threat posed by Iraq, which will also be a main topic at the summit in Prague.