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.
Parliament also adopted a law approving Saleh's longtime deputy, Vice President Abdrabuh Mansur Hadi, as consensus candidate in the election for his successor, which is due to be held on February 21.
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There had been speculation that mounting violence in the south and east between the army and Al-Qaeda linked militants might trigger a delay to the poll.
But a senior official of Saleh's General People's Congress (GPC) party, Sultan al-Barakani, insisted on Wednesday that the vote would be held on time.
The Gulf-brokered transition agreement foresees that Hadi will be the sole candidate but his nomination has been strongly criticised by the protest movement because of his close links with Saleh.
Barakani said that, ahead of the election, the veteran president, who remains in office on an honorary basis, would travel abroad.
"In the coming days, he will visit the sultanate of Oman and then Ethiopia before travelling to New York for treatment" for wounds he sustained in a bombing at the presidential palace last June, the GPC official told AFP.
"Once he has completed his treatment in New York, he will return to Yemen to continue leading the party."
Late last month, Saleh announced his intention to visit the United States "in order to create favourable conditions ... for the presidential election."
But a senior official declared shortly afterwards that the trip had been cancelled following a request from his ruling party that he remain in Yemen until after the vote.
On Tuesday, US Secretary of State Hillary Clinton criticised Saleh's failure to go abroad, saying that he had given an undertaking to do so.
"We regret that the president has yet failed to comply with his own commitment to leave the country and to permit elections," she said.
"There has been agreement with respect to the way forward that has not been fulfilled."