Article published on the 2008-04-02 Latest update 2008-04-02 13:20 TU
Bush arrived after a symbolic meeting with Ukrainian President Viktor Yushchenko and called on doubtful members to "welcome" the two former-Soviet states.
But he seems to have softened his stance slightly, saying that the summit should offer "a clear path" to reach that goal, rather than calling for an immediate decision.
French Prime Minister François Fillon yesterday told French radio station, France Inter, that the two countries joining is "not a good answer to the balance of power within Europe and between Europe and Russia".
German Chancellor Angela Merkel has said that membership should be based on the established will of the countries' people. Opinion polls in Ukraine show only about 30 per cent in favour.
RFI's Moscow correspondent, Thierry Parisot, reports that former Russian president Vladimir Putin has said that Russia will point missiles at Ukraine if it joins Nato.
On Afghanistan, Bush welcomed French president Nicolas Sarkozy's promise to send about a thousand troops.
"If we do not defeat the terrorists in Afghanistan, we will face them on our own soil," Bush told a conference organised by a German think-tank.