SOFIA, BULGARIA, JUNE 18 -- Bulgaria today became the first East European nation freely to elect a legislature dominated by communists, opting for a slow changeover to a market economy.

While Bulgaria's first free election in 58 years ends the communists' rubber-stamp domination of politics, it also ensures a sizable opposition, with enough votes to veto constitutional proposals.

"We will resolutely . . . move in the direction of a democratic European leftist party," Premier Andrei Lukanov said, expressing confidence he could form a government of consensus. But the leader of the main opposition alliance rejected any deal with the reformist communists.

According to official results of Sunday's runoff elections, the ruling Socialist Party, which the Communist Party until it changed its name in April, clinched an absolute majority with 211 seats in the 400-seat National Assembly.

The main opposition Union of Democratic Forces (UDF), a 16-party alliance, won 144 seats; the ethnic Turkish Rights and Freedoms Movement 23 seats, and the mainstream Agrarian Party 16. Smaller parties and independents won six seats.

Analysts said the Socialists represent stability for many who feared the loss of jobs and social upheaval in a quick switch to private ownership favored by the UDF. The Socialists favor leaving some industry state-run for now.

The new government must tackle the country's $10-billion foreign debt, rising inflation and shortages of basic goods. The newly elected National Assembly must also write a constitution, which requires two-thirds approval for adoption.

In an interview, Lukanov reiterated his refusal to head a cabinet composed only of members of his own party. But UDF chairman Zhelyu Zhelev said his party would not be part of a Socialist government.

Lukanov, an economist, suggested that a split in his party -- possibly at a new party congress this fall -- and in the UDF could change Bulgaria's political landscape and ensure ultimate stability.