Gabon reinforced security near public buildings after a former presidential candidate gave President Ali Bongo an ultimatum to step down and threatened to blow up government property should the nation’s leader refuse to go within three days.

Roland Desire Aba’a Minko asked Bongo to relinquish power and said that Jean Ping, declared the loser in last year’s disputed presidential vote, was the country’s leader. Aba’a Minko stood as an independent candidate in the election before withdrawing in support of Ping.

Violence won’t benefit anyone and the government is open to dialogue, Jean Boniface Assele, leader of a party allied with Bongo, said by phone. Government spokesman Bilie By-Nze didn’t answer calls seeking comment.

Minko was arrested later on Friday, Agence France-Presse reported, citing Bilie By-Nze. An investigation has been opened after armed men forced their way into some local TV stations demanding to broadcast a video with Minko’s statement, the news agency said, citing the state prosecutor.

Earlier this month, Ping called on the international community to mediate in the country’s political crisis. Bongo reached an agreement with some opposition groups last month to form a unity government, but Ping and his supporters didn’t take part in the talks. The government has rejected calls for a second round of negotiations.