An unmanned Russian cargo ship arrived Wednesday at the international space station, bearing supplies and Easter gifts from the families of the American and Russian crewmen.

The Progress M-56 ship, which was launched from the Russian-leased Baikonur cosmodrome in Kazakhstan two days ago, hooked up with the orbiting station on schedule, Russian Mission Control spokesman Valery Lyndin said.

In addition to some 2.5 tons of food, water, books, DVDs and scientific equipment, the ship is also bringing Russian cosmonaut Pavel Vinogradov and U.S. astronaut Jeffrey Williams parcels from their families.

Vinogradov and Williams on April 1 began a six-month mission aboard the space station.

Russia's Progress cargo ships and Soyuz space capsules have been the station's lifeline since the U.S. space shuttle Columbia disaster in 2003.

The shuttle program was suspended for more than two years; the shuttle Discovery flew to the station in July, but problems with its insulation raised doubts about when the next shuttle would go into space.