KINSHASA, Congo (AP) — Government, opposition and other negotiators signed an agreement Tuesday calling for Congo's next presidential vote to be held in April 2018 — more than a year after President Joseph Kabila's mandate expires.

But the biggest opposition party, which boycotted the talks, immediately rejected the deal and called for a nationwide general strike on Wednesday. Tension has mounted for well over a year around Kabila's political future, and dozens died in the capital in September when security forces clashed with anti-government protesters.

The strike proposed by the Union of Democracy and Social Progress party raised the prospect of further violence. The deal "unilaterally imposes Mr. Kabila at the head of the government in flagrant violation of the constitution," said its secretary-general, Jean Marc Kabund-a-Kabund.

The deal's signing came a day after Congo's constitutional court approved a request by the electoral commission to postpone the vote, originally expected in November, so voter registration lists could be updated.

Kabila's mandate ends in December, and the constitution prevents him from seeking a third term. Critics have accused him of orchestrating the delay to stay in power. A high court already has ruled he can stay in office until a new leader is chosen.

Kabila has not made clear whether he will seek a third term.

Tuesday's deal stipulates that an interim government led by a prime minister from the opposition be installed within three weeks, said Vital Kamerhe, the most prominent opposition representative who participated in the talks.

The agreement presents a roadmap leading to presidential, legislative and local elections on April 29, 2018, Kamerhe said. The updating of electoral rolls will be completed by July 2017, he said, and then a corps of electoral workers is called together to organize the vote.