YEREVAN, May 13 (Reuters) - Pro-presidential parties have won a large majority in Armenia's parliamentary elections, the former Soviet state's election commission said on Sunday ahead of official results.

"The Republican party won far more than other parties in the poll and is in first place," election commission spokeswoman, Tsovinar Nazaryan, said.

The Republican party is led by Prime Minister Serzh Sarksyan -- a trusted lieutenant and favoured successor to President Robert Kocharyan when he steps down next year after the end of his second term.

Christian Armenia nestles high on the southern edge of the Caucasus, a region which has emerged as a major transit route for oil from Central Asia to Europe, and also borders Turkey and Iran.

It fought a still-unresolved war with neighbouring Azerbaijan in the early 1990s and has an ongoing dispute with EU aspirant member Turkey which it accuses of killing 1.5 million of Armenians in a genocide at the end of World War One.

Nazaryan said the Republican party had won around 40 percent of the vote, and two other pro-presidential parties another 35 percent combined.

The main opposition party has about 6 percent of the vote, she said, clearing the 5 percent barrier to representation in parliament.

So far officials have counted about 60 percent of the votes and they expect to announce the final result at 2 p.m. (0900 GMT).

International observers say Armenia damaged its image as a democracy in 2003 in a parliamentary election described by monitors as falling short of democratic standards.

The monitoring group from the Organisation for Security and Cooperation in Europe (OSCE) is due to hold a news conference on Sunday at 0930 GMT.

Simmering tensions burst to the surface last month when gunmen tried to kill a senior member of the Republican party and two blasts ripped through the offices of another pro-presidential party.

The violence has revived memories of a 1999 shootout in parliament that killed the speaker and the prime minister.

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