BISHKEK (Reuters) - European observers said on Monday vote-buying and significant procedural problems marred Kyrgyzstan s presidential vote, though they praised the move towards an orderly transfer of power in the volatile ex-Soviet state. Sooronbai Jeenbekov, a protege of the outgoing president, won on Sunday with 55 percent - a stronger result than the near tie polls had predicted. Opposition leader Omurbek Babanov conceded defeat but said he would investigate irregularities. The election is seen as a test of stability in the central Asian country where Russia still holds considerable sway and two previous leaders were ousted in violent riots. Kyrgyz news website Turmush.kg published a video showing hundreds of Babanov supporters rallying outside a local government building in his home Talas region. But there were no reports of violence. The vote was competitive and candidates could, in general, campaign freely, the Organisation for Security and Cooperation in Europe (OSCE) said. But cases of misuse of public resources, pressure on voters and vote-buying remained a concern, it added. The mission s statement mentioned  numerous and significant procedural problems  during the vote count and initial stages of tabulation. But it said the election had  contributed to the strengthening of democratic institutions by providing for an orderly transfer of power .     An official confirmation of the figures is expected within a week. A unchallenged result would mark the first peaceful transition of power between full-time presidents in the mostly Muslim nation.  Pre-election polls had suggested both candidates would fail to get 50 percent and have to proceed to a second-round runoff. Russian President Vladimir Putin on Monday became the first foreign leader to congratulate Jeenbekov on his victory. Outgoing President Almazbek Atambayev - who developed particularly close ties with Moscow during his six years in office - dismissed Western criticism as biased.  Of course, they would be singing praise if a pro-American candidate won the election,  Kyrgyz news website 24.kg quoted him as telling foreign diplomats in a meeting on Monday. Both candidates differed little on the main points of policy during the campaign: a secular state and hewing close to Russia in a region where Moscow vies for influence with the United States and China. However, they represent rival interest groups and clans inside Kyrgyzstan that are fighting for access to power and state resources. Atambayev and Jeenbekov s Social Democratic party has the biggest faction in parliament and dominates the coalition cabinet. Jeenbekov has pledged to continue his predecessor s policies. Kyrgyzstan hosts a Russian military base.  