The Kremlin's rejection on Tuesday of Bush's accusation that Russia is no longer striving for democracy comes as tensions are already high between the one-time Cold War rivals over a planned US missile defense system in Central Europe. This latest diplomatic exchange will do little to ease the strain.

"We cannot agree on his declaration about the derailing of democratic reforms," Kremlin spokesman Dmitry Peskov told reporters ahead of a meeting of Group of Eight leaders in Germany.

"Russia is a democratic country that shares common world and common European values."

Earlier Bush said during a speech in Prague: "In Russia, reforms that once promised to empower citizens have been derailed, with troubling implications for democratic development."

On the attack

Peskov reiterated Russia's frequent complaint about US unilateralism, saying "one-sided decisions and double standards are inacceptable."

He also renewed Moscow's attack on the US plan to deploy an anti-missile system in the Czech Republic and Poland, both former Warsaw Pact countries that are now members of NATO and the European Union.

"We have not received an explanation on the point of this shield or an explanation about whom it targets," Peskov said.

The United States says the shield would guard against hypothetical future attacks from Iran or North Korea, neither of which are believed currently to possess missiles of a sufficient range to reach Europe.

Moscow describes the planned missile shield as an aggressive step closer to Russia's borders.

Addressed at summit

Peskov said that "these painful questions" would be raised during the G8 summit starting Wednesday, including during a meeting scheduled for Thursday between Putin and Bush.

Russia will openly talk of its concerns and will wait for a corresponding explanation and, of course, the president as always will be ready to give detailed explanations on questions of concern to our partners," Peskov said.

However, he said he hoped the worsening rhetoric between Moscow and Washington will not "create any tension, much less confrontation."