Tunisia's main trade union confederation called Monday for mass protests to pressure the Islamist-led government to accept a compromise roadmap for ending two months of political deadlock.
The UGTT announced that it would mobilise a "large, peaceful protest" in Tunis and gatherings in all regions of the country, without saying when.
"We have decided to activate all forms of peaceful civilian protest in all sectors," added the powerful union confederation, which boasts some 500,000 members and is capable of bringing the country to a standstill.
"The ruling troika puts its own interests first, and seeks to remain in power at the expense of the interests of the nation and the people."
The UGTT has been the lead mediator between the government and the mainly secular opposition, despite its tense relations with the Islamist Ennahda party that leads the ruling coalition.
"The ruling troika (Ennahda and its two coalition partners) puts its own interests first, and seeks to remain in power at the expense of the interests of the nation and the people," the UGTT said.
It promised to coordinate its actions with the other three mediators -- employers' organisation Utica, the Tunisian League for Human Rights and the bar association.
The mediators accuse Ennahda of "ambiguities" in its response to their blueprint for ending the crisis triggered by the July assassination of opposition MP Mohamed Brahmi by suspected hardline Islamists.
The plan, which the mediators say has been accepted by the opposition, sets a three-week deadline for the formation of a cabinet of independents to replace the current Ennahda-led government after the launch of a dialogue between the two sides.
It also sets a four-week deadline for the adoption of a new electoral law, the announcement of a timetable for fresh elections and the completion of a long-delayed draft constitution.
In its response, Ennahda gave a tighter deadline for the completion of the draft charter but did not spell out its position on the timetable for a new government.
The UGTT charges that Ennahda has done "everything to make the plan fail," while misleading public opinion through the media by claiming that it had accepted the initiative.
The Islamists have rejected those accusations, saying the party accepts the initiative and calling for "immediate talks on drawing up the constitution, a timetable for elections and forming a government."
Prompt replacement of the existing administration has been a persistent demand of the opposition since Brahmi's murder.
The opposition says Ennahda has not done enough to rein in Islamist militants, whose influence has grown since the 2011 uprising that toppled veteran president Zine El Abidine Ben Ali, and has not improved economic conditions.