Russia's Interior Ministry says Boris Nemtsov, a leading opposition figure and former deputy prime minister, has been shot and killed near the Kremlin.

Nemtsov, a sharp critic of President Vladimir Putin, was killed early Saturday. His death comes just a day before a major opposition rally in Moscow.

The Interior Ministry, which oversees Russia's police force, said that Nemtsov was shot four times from a passing car as he was walking a bridge just outside the Kremlin.

Nemtsov served a deputy prime minister in the 1990s and later became a prominent opponent to Putin, helping organize street protests and exposing official corruption.