Raul Khajimba, leader of the self-proclaimed breakaway Georgian region of Abkhazia, has resigned following four days of protests in the regional capital, Sukhumi.
Former Abkhaz Prime Minister Sergei Shamba read Khajimba's resignation statement to protesters near the presidential residence late on January 12.
Parliament speaker Valery Kvarchia confirmed the resignation, telling Russia's TASS news agency that "the issue of who will act [as president] has not yet been decided."
"It may be the prime minister," he added, referring to Prime Minister Valery Bganba.
Kvarchia said the region's de facto legislature would take up the issue in a session on January 13.
The announcement came just hours after Russian presidential aide Vladislav Surkov arrived in Sukhumi, joining a Russian delegation headed by Russian Deputy Security Council Chairman Rashid Nurgaliyev.
The crisis in the breakaway Georgian region erupted on January 9, when demonstrators stormed the Sukhumi building housing Khajimba's administration, asserting the September election that he won was fraudulent.
The legislature later called on Khajimba to step down. The Abkhaz Supreme Court on January 10 reversed an earlier decision and declared the September results void, following a petition by opposition leader Alkhas Kvitsinia.
Khajimba and his supporters resisted the calls for his resignation and planned to launch legal appeals before his January 12 about-face.
The head of the region's self-proclaimed Central Election Commission, Tamaz Gogia, said on January 12 that he did not agree with the Supreme Court ruling, but that he would abide by it.
The commission set March 22 as the date for a new election.
The Black Sea region has had de facto independence from Georgia since a war against Tbilisi in 1992-93. After Russia and Georgia fought a five-day war in August 2008, Moscow unilaterally recognized Abkhazia and another breakaway Georgian region, South Ossetia, as independent states.
Both regions have since been largely propped up by Moscow and are hosting Russian military forces.
Georgia and most of the international community consider both regions to be occupied territories.