PODGORICA, Montenegro (AP) — A former intelligence chief has been formally appointed as the new Montenegrin prime minister-designate following last month's tense elections.

Dusko Markovic will replace long-ruling premier Milo Djukanovic who has brought the small Balkan country to the doorstep of NATO membership.

Markovic is a close ally and a deputy of Djukanovic. Their ruling Democratic Party of Socialists has been in power in Montenegro for over 25 years.

President Filip Vujanovic appointed Markovic on Wednesday after DSP won the most votes in the Oct. 16 election. The party will have to seek a coalition with smaller groups.

Opposition parties have rejected the election result, claiming irregularities.

The vote was marked by an alleged foiled coup attempt orchestrated by Russian nationalists to block Montenegro's NATO bid.