"Fifty-four protesters were arrested during a rally in Sulaimaniyah" on Sunday by Kurdish security forces, in the south of the autonomous northern Iraqi region, Mohammed Abdallah, head of the Movement for the Freedom of Kurdistan Society, told AFP.

Abdallah, whose party is close to the PKK, said that some of those arrested were subjected to "violence, beatings and insults by the police".

Kurdish authorities have not provided any details on the purported arrests and it is not known if charges have been brought.

The demonstration was organised the day after the Turkish military launched a cross-border ground and air operation against the PKK in the north of Iraqi Kurdistan near the Turkish border, Abdallah said.

The PKK, classified as a "terrorist" group by Ankara, has waged an insurgency against the Turkish state since 1984, resulting in over 40,000 deaths.

It has long used the rugged terrain of northern Iraq as a rear base to wage attacks on Turkey, which in turn set up military positions inside Iraqi territory to fight them.

Nine women and a journalist -- Rebaz Hassan of the pro-PKK news agency Firat -- were among those arrested, Abdallah said.

The journalist was released along with 15 others, but the rest "remain in detention," he said.

Turkey regularly launches attacks against PKK installations in northern Iraq.

Iraqi authorities have protested against those military operations, but Turkey defends its right to bomb the PKK and accuses Baghdad and Iraqi Kurdistan of turning a blind eye to the group's activities.

Human rights associations regularly criticise Iraqi Kurdish authorities for carrying out arbitrary arrests, suppressing protests and attacking press freedoms.

In Sulaimaniyah last year, eight protesters died and dozens were arrested amid anti-government rallies over delayed public sector salaries and pay cuts. Families of some of the youths who died in that unrest are still awaiting justice.