The Yemeni parliament adopted on Saturday a law giving veteran President Ali Abdullah Saleh immunity from prosecution in return for stepping down under a Gulf-brokered transition deal.

The law adopted gives Saleh, in power since 1978, "complete" immunity, and also offers partial protection from legal action to his aides.

The final text says Saleh's lieutenants cannot face prosecution for "actions that were politically motivated and carried out in the exercise of their duties," but specifies that the amnesty "does not apply to acts of terrorism."

The transitional government of national unity, which is led by the parliamentary opposition, had submitted 11th-hour amendments on Friday reducing the scope of the amnesty offered to the president's aides following a public outcry.

The immunity pledge, which was a key element of the hard-won Gulf deal that Saleh signed in November, has been strongly criticised by Western human rights groups and the United Nations.

UN High Commissioner for Human Rights Navi Pillay said earlier this month that anyone who had committed abuses during the mass protests in Yemen that erupted in January last year must not be allowed to evade justice.

Pillay urged decision-makers in Yemen to respect the prohibition in international law against amnesties for gross human rights violations.

Leaders of the protest movement have also kept up demonstrations against the immunity pledge demanding that Saleh and his cohorts be put on trial.