Image caption Anti-government protesters have blamed Ennahda for the death of murdered opposition leader Mohammed Brahmi

Tunisia's Islamist-led government has agreed to resign after talks with opponents that are to start next week.

It is hoped a caretaker government will be negotiated over the next three weeks that will prepare for new elections.

The decision marks a breakthrough in weeks of crisis involving the ruling coalition, led by the Islamist Ennahda party, and the secular opposition.

Anti-government protests intensified recently after the killing of two opposition figures.

The crisis has threatened to disrupt a transition to democracy that began after Tunisians threw out their decades-old authoritarian government at the beginning of the 2011 Arab Spring uprisings.

The talks were announced on Saturday by the powerful UGTT labour union, which will act as a mediator.

The union urged both sides to set a date for next week.

Under the deal, the Ennahda party has agreed to three weeks of talks, after which it will hand power to an independent transition leadership and set a date for parliamentary and presidential elections.

Image caption In February, the murder of Chokri Belaid brought down the first Islamist-led government

"The dialogue will start on Monday or Tuesday," said Lotfi Zitoun, an Ennahda party official, according to Reuters.

"Ennahda has accepted the plan without conditions to get the country out of the political crisis."

While Tunisia's uprising spread through the Arab world, efforts to strengthen democracy at home have stalled due to political antagonism.

The opposition has accused the Ennahda party of pushing an Islamist agenda in the previously secular nation.

Threat of deadlock

The rivalry intensified this year after the murders of opposition politician Mohammed Brahmi in July and Chokri Belaid, a prominent leftist, in February.

The moderate Islamist government has blamed hardliners for the killings but the National Salvation Front-led opposition has accused Ennahda of failing to rein in radical Islamists.

Before the 2011 ousting of Tunisia's longtime leader, Zine al-Abidine Ben Ali, the country had been known as one of the most secular in the Arab world.

The opposition has accused Ennahda of being too tolerant of radical Islamists trends.

Analysts say the talks could struggle to break a deadlock if the rival parties are unable to overcome differences over a new constitution and the running of elections.