ABUJA, Nigeria (AP) -- Parliament empowered Vice President Goodluck Jonathan on Tuesday to take over for the ill president of oil-rich Nigeria, whose absence has stoked unrest in Africa's most populous country.
Both the House of Representatives and the Senate passed measures calling on Jonathan to act as president and commander in chief until President Umaru Yar'Adua returns from Saudi Arabia, where he has been receiving medical treatment for a heart condition since November.
Yar'Adua's absence has caused a cease-fire with militants in the oil-rich delta to unravel and had left no one formally in charge of the nation of 150 million. The crisis in a powerful country with a long history of coups and military dictatorships has drawn international attention, with U.S. Secretary of State Hillary Clinton and European leaders calling on the nation to follow its constitution.
Newspapers began worrying about possible coup scenarios as Yar'Adua's absence grew longer. However, military leaders said several weeks ago they had no ambitions to take power and would respect the constitution.
It was unclear when Jonathan would be sworn in as president.
The National Assembly's empowering of Jonathan may set the stage for new legal battles and power struggles. The motion would allow Yar'Adua to reassume the presidency if he returns to the country healthy enough to lead the nation. However, many have worried the president may be too seriously ill to serve again, throwing into question who will lead the ruling party in the 2011 presidential election.
Yar'Adua, who long has suffered from kidney ailments, left Nigeria for Saudi Arabia on Nov. 23. He was admitted to a hospital the next day for what his physician says Yar'Adua is acute pericarditis, an inflammation of the sac surrounding the heart.
Since Yar'Adua left Nigeria, a major kidnapping and a pipeline attack have occurred in the oil-rich Niger Delta. Religious violence between Christians and Muslims in central Nigeria also left more than 300 dead and thousands displaced. And a young Nigerian attempted to bring down a trans-Atlantic flight bound for Detroit, sparking tighter security regulations for travelers from the West African nation.
While Nigerian law allows for a smooth transition of power from Yar'Adua to the vice president, the 58-year-old president left without following any of those procedures. The federal government says Jonathan has been acting in Yar'Adua's place without the constitutional procedures but protesters have taken to the streets, saying the country was essentially leaderless. Several former Nigerian leaders have urged Yar'Adua to step down if he is medically unfit to serve.
Parliament's action on Tuesday could disrupt an unwritten power-sharing agreement between Nigeria's Christian south and the Muslim north. Jonathan, a Christian, would be taking over for Yar'Adua, a Muslim, before his appointed time was up.
Yar'Adua has given one interview since being out of the country. In January, he told the BBC over the phone that he hoped to recover and return to power.