Both houses of Nigeria’s National Assembly have passed a motion for sick President Umaru Yar’Adua to hand power to his deputy until he recovers.

The BBC’s Ahmed Idris in Abuja says the move among the political elite to back the vice-president is unprecedented.

Mr Yar’Adua has been in hospital in Saudi Arabia since last November.

His allies have been loath to see Vice-President Goodluck Jonathan sworn in as acting president because of Nigeria’s delicate regional balance of power.

Mr Yar’Adua is a northerner while Mr Jonathan is from the south.

Since democracy returned to Nigeria in 1999, power has alternated between north and south and some northern power-brokers do not want to see their “turn” cut short.

Mr Yar’Adua’s absence has sparked legal challenges, cabinet splits and mass protests.

It has led to a freeze in government business and threatens progress made in halting unrest in the oil-rich Niger Delta.

Cabinet challenge

Our correspondent says members of the Senate and House of Representatives and state governors are usually loyal to the president, and the office of vice-president carries little weight.

YAR’ADUA ILLNESS TIMELINE 23 November 2009 Goes to hospital in Saudi Arabia 26 November Presidential doctors say he has pericarditis – inflammation of the heart lining 23 December First court case filed urging him to step down 5 January 2010 Two more court cases filed, rights group wants president declared “missing” 12 January President gives first interview from Saudi Arabia 27 January Cabinet declares president fit 29 January Court says no need for formal transfer of power

But the governors decided last week to back Mr Jonathan to become acting president and have been lobbying senators ever since.

The Senate carried the motion declaring that Mr Jonathan “shall henceforth discharge the functions of the office of president, commander-in-chief of the armed forces of the federation, as acting president”.

But it is unclear what the next step will be.

Some analysts have suggested the assembly’s motion is not legally binding and could face court challenges.

Others say the move has laid down a challenge to the cabinet – due to meet on Wednesday – and presidency to accept the handover, or risk inflaming public opinion.

The cabinet has previously insisted that the president is able to continue in office, although splits subsequently emerged within ministerial ranks.