Nigeria's ruling party in split

Attempts to extend Mr Obasanjo's tenure also divided the country

Nigerian riot police in the capital Abuja have sealed the offices of a splinter group of the ruling PDP party, following a split on Friday.

The division occurred as prominent party members opposed efforts to amend the constitution to allow the president a third term in office.

Vice-president Atiku Abubakar, who was against the change, says he will run for president in next year's elections.

Nigeria's Senate last month threw out the amendment.

But the move had already divided the party, with President Olusegun Obasanjo and his deputy calling for each other to stand down.

They have been president and vice-president since the end of military rule in 1999.