MOSCOW—Russian President Dmitry Medvedev Thursday endorsed a controversial draft law that would expand the powers of the Federal Security Service, the KGB’s main successor. The plan has triggered fierce opposition from human-rights groups.

In his first public comments on the draft, which was approved in the lower house of parliament Friday, Mr. Medvedev told a joint news conference with German Chancellor Angela Merkel that he had ordered the proposed changes, which he defended as a routine domestic matter.

Ms. Merkel said the issue had come up in talks between the two presidents in Yekaterinburg Wednesday. She cited “different assessments” of human-rights and civil-society issues between Germany and Russia but stopped short of criticizing the draft law.

Domestic critics said Mr. Medvedev’s support for the plan is at odds with his pledges to increase political openness and shore up the rule of law. Kremlin opponents say the proposal is the latest in a series of measures that amount to a tightening of state control.

“The president has said publicly today that there’s no hope for liberalization of the regime,” said Lev Ponomaryov, head of the nongovernmental group For Human Rights and a member of a Kremlin advisory panel that recommended against passage of the plan last month. “It’s an absolutely totalitarian law,” he added.

Supporters of the law—which was virtually assured of passage thanks to the commanding majorities held by the pro-Kremlin United Russia party in both houses of parliament—deny the plan represents an effort to tighten the screws on critics. They argue that it gives the Security Service, known by its Russian initials FSB, necessary powers to fight terrorism and extremism.

-> Wall Street Journal online