Russian President Vladimir Putin will visit ex-Soviet Uzbekistan Tuesday to pay his respects at the grave of strongman leader Islam Karimov, who was buried over the weekend.

"I think that tomorrow I will definitely stop over to pay my respects," Putin said Monday at a press conference following the G20 summit in the Chinese city of Hangzhou.

Karimov, 78, was pronounced dead late Friday after suffering a stroke and falling into a coma, Uzbek authorities said, following days of speculation about his rapidly failing health.

Karimov led the ex-Soviet state with an iron grip for some 27 years, earning a reputation abroad as one of the region's most savage despots who ruthlessly stamped out opposition.

The veteran leader portrayed himself as a bulwark against radical Islam in a volatile region and played Russia, the West and China off against each other to avoid isolation.

Karimov's death and the absence of a clear successor has brought much uncertainty to the country, which has never held elections deemed free and fair by international monitors.

Putin -- who did not attend Karimov's funeral in his home city of Samarkand in southeastern Uzbekistan on Saturday -- said that his death was a "great loss" for the country.

"There are many ways to assess different episodes in Uzbekistan's recent history," Putin said. "But he (Karimov) preserved stability in the country, he preserved progressive development."

Putin also expressed the hope that the new Uzbek leadership would maintain the stability found under Karimov.

Under Uzbek law, senate head Nigmatulla Yuldashev has become acting president until early elections are held.

But the frontrunner to replace Karimov appears to be Prime Minister Shavkat Mirziyoyev, known as a technocrat enforcer, after he headed the committee that organised Karimov's funeral and led the tributes on Saturday.