Moscow ? A senior Russian official warned Wednesday that Moscow could put new missiles in western Russia if Washington pursues plans to build a missile defense system in the Czech Republic and Poland.

President Vladimir Putin, who has suggested alternatives to the U.S. plan, said he is sure Russia and the United States can continue to work together despite disagreements. President Bush and Putin met this week at the Bush family home in Kennebunkport, Maine, in an effort to halt the deterioration in U.S.-Russian relations.

Sergei Ivanov, a first deputy prime minister and former defense minister, said Russia would not need to rethink its missile deployments if Washington drops its plans to build the system in Central Europe and accepts Putin’s proposal to expand the system and use Russian installations.

But Ivanov, considered a leading contender to win Putin’s endorsement in the March presidential contest, warned there would be consequences if the U.S. does not compromise on the issue.