|Yemen's parliament has granted Saleh complete immunity from prosecution in return for his stepping down [AFP]
Ali Abdullah Saleh, Yemen's outgoing president, is travelling to the United States for medical treatment, according to the country's SABA state news agency.
Saleh boarded a transatlantic flight after a short stopover in neighbouring Oman on Monday, though US officials maintained his stay in the country would be temporary.
"As we have indicated, the sole purpose of this travel is for medical treatment and we expect that he will stay for a limited time that corresponds to the duration of this treatment," the US state department said in a statement on Sunday.
Saleh left Sanaa airport, the Yemeni capital, aboard a private Saudi plane on Sunday evening, according to the Yemeni news website Mareb Press.
"God willing, I will leave for treatment in the United States and I will return to Sanaa as head of the General People's Congress party"
- Ali Abdullah Saleh, Yemeni president
In an address to Yemeni media earlier in the day said he would return to the country as head of the ruling General People's Congress party.
"I ask for forgiveness from all my people, men and women, for any shortcomings during my 33-year-long rule," he said, according to SABA.
Sultan al-Barakani, a senior official of the GPC party, said last week that the 69-year-old president would visit Oman and then Ethiopia before travelling to New York for treatment for wounds he sustained in a bombing at the presidential palace last June.
'Execute the butcher'
Meanwhile, tens of thousands of Yemenis staged protests on Sunday against a law granting immunity for Saleh, from prosecution over a deadly crackdown on dissent.
The protesters carried banners during Sunday's rallies in Sanaa calling on parliament members to reverse their decision.
"It is our duty... to execute the butcher," chanted the protesters gathered in Change Square, the centre of the democracy movement that has been calling for Saleh's removal since January last year.
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The demonstrators tried to march to the US embassy but were stopped by Yemeni security forces.
"To the politicians, we say there will be no immunity at the expense of the blood of our martyrs," the protesters said, referring to the hundreds killed in the government crackdown.
Saleh's immunity is part of a Gulf Co-operation Council-negotiated power transition deal aimed at ending the unrest in the country.
Early presidential elections are scheduled to be held on February 21.
Yemen's parliament adopted the law on Saturday giving Saleh "complete" immunity from prosecution in return for stepping down.
Parliament also adopted a law approving Saleh's longtime deputy, vice-president Abd-Rabbu Mansour Hadi, as the consensus candidate in the election for Saleh's successor.
The law offers partial protection from legal action for Saleh's aides, saying they cannot face prosecution for "actions that were politically motivated and carried out in the exercise of their duties."
The final text of the immunity law specified that the amnesty "does not apply to acts of terrorism", though no further details were revealed as to what actions may fall within that category.
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The UN envoy to Yemen, Jamal Benomar, has criticised the immunity law, arguing that it neglects the rights of "victims".
Speaking before departing Yemen late on Saturday, Benomar said that though "the law was amended ... it does not live up to our expectations.
"The UN in principle stands against this type of blanket immunity."
Benomar further called on the Yemeni parliament to enact a "transitional justice and reconciliation" law that would allow victims to be heard and make claims for compensation.
He said the UN could not condone a broad amnesty that covered crimes against humanity, war crimes or gross violations of human rights.
Source: Al Jazeera and agencies