(BBC)- US President George W Bush is to go to Russia to meet President Vladimir Putin for the last in a series of scheduled talks between the two leaders.
The meeting, in Sochi, follows a summit in Romania where Mr Putin warned against the bloc's eastward expansion.
Mr Bush is currently in the Croatian capital Zagreb.
Correspondents say the visit there is a chance for him to congratulate the Balkan state on its invitation to join Nato and celebrate its role as US ally.
Several thousand people are expected to hear Mr Bush's speech at a historic central Zagreb square.
The BBC's Helen Fawkes in Zagreb said the transformation of the former Yugoslav republic sent out an important message to other countries in the Balkans.
Mr Bush is due to fly to Sochi on Russia's Black Sea coast later on Saturday to meet the Russian president.
Mr Putin leaves office next month, though he is expected to serve as prime minister under President-elect Dmitry Medvedev.
Russia expressed its opposition to Nato plans to expand eastward at the summit, after news that the former Soviet states of Georgia and Ukraine had been offered Membership Action Plans, the first step in becoming members of the security pact.
The two leaders are expected to discuss US plans to site a missile defence system in Eastern Europe.
Russia has strongly criticised the US proposals, which would see interceptor missiles based in Poland and a radar system in the Czech Republic.
Nato countries agreed to back US plans to site a missile defence system in the two countries at the Bucharest summit.