Thousands of protesters massed in the Armenian capital today and demanded a recount in a presidential vote in which preliminary results showed incumbent Robert Kocharian opening up a big lead but falling just short of outright victory.

Up to 25,000 demonstrators poured into a snow-covered square in front of Yerevan's history museum for a second day, chanting the name of challenger Stepan Demirchian, who held second place. Many carried his portrait aloft.

Demirchian, son of a Communist-era leader, said he would wait until Saturday's official announcement of first-round results before determining his next move. A runoff pitting him against Kocharian would take place March 5.

"The support of the people is obvious," he said of the crowds of protesters, some of whom perched on rooftops or in trees. "I am sure that I will win." He later added: "It is obvious the results have been falsified, and we demand a recount. I'm ready for the runoff."

The opposition accuses Kocharian's supporters of stuffing ballot boxes, irregularities in the counting of votes and intimidating voters at polling stations. Observers from the Organization for Security and Cooperation in Europe and the Council of Europe said they found less evidence of fraud than in previous elections.

Aram Sargsian, a prominent opposition politician and the brother of a former prime minister, told the protesters: "There should be no second round. We should have a declaration of Demirchian's victory."

Few police officers were in evidence and demonstrators dispersed without incident.

Kocharian has not appeared in public since the preliminary results were announced Thursday, but his election team was confident of a second-round victory. "This is a good result, a good basis for the second round. I'm sure we will win," said the president's campaign chief, Serzh Sargsian.

Kocharian, who is seeking a second five-year term, was credited with 49.8 percent of the vote in Wednesday's poll, just short of the 50 percent needed for a first-round win. Demirchian was second in a field of nine candidates with 28.3 percent.

Artashes Gegamian, a former mayor of Yerevan, came in third with 17 percent and is now critical to the outcome. He has yet to announce his support for either finalist.

Demirchian is the son of Karen Demirchian, the Communist Party leader in the 1970s and '80s, when Armenia was a Soviet republic. Karen Demirchian, who was defeated by Kocharian in the 1998 presidential election, was killed in an attack on parliament in 1999.

Political analysts say most voters were concerned with economic issues amid widespread poverty and average monthly wages equivalent to $40. But the winner will also have to tackle a protracted dispute with neighboring Azerbaijan over the Nagorno-Karabakh enclave in a region critical to Western oil interests.

Nagorno-Karabakh's ethnic Armenians broke away from Azerbaijan in 1988. Six years of fighting left more than 35,000 dead and a million homeless. A cease-fire took hold in 1994, but the issue has defied a long-term solution.