Russian President Dmitry Medvedev has appointed Russia's NATO envoy as deputy prime minister in charge of the country's defense sector.

Dmitry Rogozin was named to the post Friday. He replaces Sergei Ivanov, who was named Kremlin chief of staff on Thursday.

The appointments are part of a government reshuffle ahead of presidential elections set for March 4. They follow mass protests against election fraud in the country's parliamentary poll earlier this month.

More than 50,000 Russians have signed up to participate in the next opposition-led demonstration on Saturday in Moscow.

Tens of thousands of people have previously taken to the streets in Moscow and elsewhere demanding a rerun of the December 4 vote, in the largest demonstrations in post-Soviet Russia.

Mr. Medvedev and Prime Minister Vladimir Putin have opposed repeating the election, in which Mr. Putin's ruling United Russia party won 238 of the 450 seats in parliament.

Opposition leaders say widespread fraud in the December 4 parliamentary elections raised the ruling party's return from one-third of the vote to one-half.

On Thursday, Mr. Medvedev proposed political reforms, including easing registration requirements for political parties and presidential candidates.

He also said he supports a proposal under consideration by Mr. Putin that allows direct election of governors pending Kremlin approval of candidates.