U.S. President George W. Bush and Russian President Vladimir Putin meet Thursday in Germany amid renewed tensions between the two sides.

The presidents will hold talks on the sidelines of the Group of Eight summit at the German Baltic Sea port of Heiligendamm.

Mr. Putin is angry at U.S. plans to install a missile defense system in Europe, calling it a threat to Russian security, and he vowed to aim his nation's missiles at the region if the system is built.

Mr. Bush played down Mr. Putin's threat, saying Russia is not an enemy and is not going to attack Europe. But he has criticized Moscow for backsliding on promised democratic reforms -- a charge Russia denies.

Moscow also strongly opposes U.S. support for supervised independence for Kosovo -- an ethnic Albanian majority province in Serbia.

Separately, President Bush holds talks today with British Prime Minister Tony Blair, who is attending his last G8 summit before leaving office later this month.

The G8 leaders hold their first working sessions today. Summit host and German Chancellor Angela Merkel has put global warming at the top of the summit agenda. Aid to Africa will also be a major topic.

Mrs. Merkel wants the world's eight major industrialized nations to agree to cut greenhouse gases blamed for global warming in half by 2050. A Bush administration official stressed Wednesday that Washington will not agree to any targets or timetables at the summit.

Last week, President Bush called for the world's top 15 greenhouse gas producers to set a goal by the end of 2008 to cut emissions.

The G8 members are Britain, Canada, France, Germany, Italy, Japan, Russia, and the United States. Leaders from China, India, Brazil, Mexico, and a number of African countries are also attending the summit.

Some information for this report was provided by Reuters and AFP