Russia's lower house of Parliament, the State Duma, has rejected calls for Prime Minister Vladimir Putin to speed up the signing of an agreement to suspend the adoption of Russian children by U.S. citizens.

Russia is one of the largest sources of adoptions to the United States, accounting for about 10% of foreign adoptions, but the issue has become controversial in recent years following numerous incidents involving the mistreatment of Russian adopted children in the United States.

In the latest case, a U.S. woman sent her seven-year-old adopted son back to Russia on a one-way flight claiming he was "psychopathic."

After this case the Russian foreign minister Sergei Lavrov said Russia could freeze child adoptions by U.S. citizens until the countries sign an intergovernmental agreement on adoptions.

Deputies from several parties in the State Duma wrote to Putin asking him to speed up the signing of the adoption agreement.

First deputy chairman of the Duma women, children and family affairs committee Natalia Karpovich said talks with the U.S. side on signing the adoption agreement are currently underway.

"If the agreement is not signed, we will be the first to introduce a ban on [foreign] adoption," Karpovich said.

She said the premier is not empowered to suspend the adoption of Russia children by foreign citizens.

MOSCOW, May 7 (RIA Novosti)