Boris Yeltsin, who engineered the final collapse of the Soviet Union, has died aged 76, a Kremlin official said today.

As the country's first post-Communist president he pushed Russia to embrace democracy and market economy.

Kremlin spokesman Alexander Smirnov said Yeltsin died, but gave no cause of death or further information.

The Interfax news agency cited an unidentified medical source as saying he had died of heart failure.

Although Yeltsin was initially admired abroad for his defiance of the monolithic social system, many Russians will remember him mostly for presiding over the steep decline of their nation.

He was a contradictory figure, rocketing to popularity in the Communist era on pledges to fight corruption - but proving unable, or unwilling, to prevent the looting of state industry as it moved into private hands during his nine years as Russia's first freely elected president.

He also led Russia into a humiliating war against separatist rebels in Chechnya that ended with Russia's pullout.

Yeltsin, who suffered from severe heart problems during his time in office, resigned on New Year's Eve 1999, several months before his term was to end.