Tunisia's main trade union confederation, the UGTT, lashed out on Saturday at the Islamist-led government for failing to crack down on a militia for attacking their headquarters in December.
General Union of Tunisian Workers secretary general Houcine Abassi accused the government of lacking the "political will to recognise that the UGTT was attacked by the League for Protecting the Revolution (LPR)," a group said to support the government.
Several dozen alleged members of the LPR attacked union members on December 4 outside their Tunis headquarters as they gathered to mark the 60th anniversary of the assassination of their founder.
Government members of the commission of inquiry into the incident did not accept union claims that the LPR was trying to "use violence to pressure the UGTT into accepting the government's wishes."
A final report into the fighting, which had been due in January, has yet to be published.
Relations between the UGTT and Ennahda, the Islamist party that heads the government coalition, are already tense.
The UGTT, which has several hundred thousand members, and Ennahda, regularly trade accusations. Most recently the union accused Ennahda of trying to curtail the right to strike in the new constitution that is being drafted.
Ennahda believes the UGTT is partly responsible for rising tensions by ramping up strikes that knock out entire sectors of the economy. A general strike called by the UGTT after the February murder of anti-Islamist politician Chokri Belaid paralysed the country.
These disputes and the violence that accompanies them have made foreign investors skittish.