MOSCOW (Reuters) - Armenia's opposition alliance, led by former president Robert Kocharyan, has asked the constitutional court to overturn the results of a June 20 election which it lost, the TASS news agency cited the group as saying on Friday.

       Acting prime minister Nikol Pashinyan's party won 53.91% of the vote at parliamentary elections last month with Kocharyan's Armenia political bloc trailing with 21.9%.

       International observers from the Organization for Security and Co-operation in Europe (OSCE) said the elections were competitive and generally well-managed.

       Pashinyan called the election early in a bid to quell a political crisis that began when ethnic Armenian forces lost control of territory in and around Nagorno-Karabakh in fighting with Azeri forces last year.

       (Reporting by Maria Kiselyova; writing by Tom Balmforth; editing by Andrew Osborn)