Russia will consider taking retaliatory measures against new sanctions announced by the U.S. over Moscow's alleged involvement in a nerve-agent attack in the U.K., according to Russian Foreign Ministry Spokeswoman Maria Zakharova.

Zakharova said Russia does not intend to increase tensions and that retaliatory measures will depend on the restrictions imposed by the U.S., Russian news agency TASS reported.

"The Russian side will engage in working out retaliation measures to a new unfriendly move by Washington," Zakharova said, adding that U.S. conditions for lifting the sanctions were "unacceptable."

But Dmitry Peskov, spokesman for Russian President Vladimir Putin, took a softer tone, saying it was premature to talk about retaliatory measures. He nonetheless called the sanctions "illegitimate" and denied that Russia was involved in the incident.

Moscow has been accused of using a nerve agent in an attempt to assassinate U.K. citizen and former Russian spy Sergei Skripal and his daughter in March.

The latest U.S. sanctions, which could include a ban on exports of national-security-sensitive goods and technology to Russia, are expected to take effect on or around Aug. 22, according to the U.S. State Department.