Democratic Republic of Congo is unlikely to hold a presidential election as scheduled in November, the U.N. head of mission there said on Thursday, something that U.N. experts have warned could trigger violent political unrest.

President Joseph Kabila, in power since 2001, is bound by term limits to step down after having won elections in 2006 and 2011, but opponents accuse him of deliberately delaying the Nov. 27 poll to cling to power.

“I do not see the elections (taking place) on Nov. 27,” U.N. mission chief Maman Sidikou told a news conference in Kinshasa.

In March, the U.N. Security Council called on the country to organize the election this year, but the government says logistical and budgetary obstacles make it unrealistic. The election commission has said it needs more than a year to update voter rolls.

The country’s highest court ruled in May that Kabila would remain in power until the election is held.

“It is the Congolese who will decide when the elections will take place,” Sidikou said.

He urged political leaders to join a national dialogue called for by Kabila but which has been boycotted by leading opposition parties.

The largest opposition party, the Union for Democracy and Social Progress, said this week that its president, 83-year-old Etienne Tshisekedi, would return to Congo to attend a July 31 rally and participate in an eventual dialogue.

Tshisekedi, the runner-up to Kabila in the 2011 election that observers said was tainted by widespread fraud, has been in Belgium since August 2014 receiving medical treatment.