SOFIA (Reuters) - Bulgarian Socialist ally Rumen Radev, a Russia-friendly newcomer to politics, won the Bulgarian presidential election, partial official results showed on Monday.

Former air force commander Radev won 59.4 percent of the vote, compared with 36.2 percent for the candidate of the ruling center-right GERB party, Tsetska Tsacheva, with 99.3 percent of polling stations counted.

The results, which reflected exit polls, meant Radev will take office for a 5-year term on Jan. 22 next year.

(Reporting by Tsvetelia Tsolova; Editing by Stephen Coates)