ABUJA (REUTERS) - Nigerian police fired tear gas in the lobby of parliament on Thursday to stop the speaker of the lower house entering with a crowd of lawmakers and supporters, prompting the chairman to shut the national assembly.
Parliament was convening for the first time since Aminu Tambuwal, whose post is the fourth most powerful in the country, switched sides before presidential elections in February to join the opposition to President Goodluck Jonathan.
The confrontation started when Tambuwal appeared at the gates of parliament accompanied by a crowd including members of the opposition All Progressive Congress (APC) to preside over debate on a Bill to extend a state of emergency in three states hit by insurgency.
After an argument, police locked the gates and the crowd scaled the walls and gate to force their way in, witnesses said.
Many fled after the police fired the tear gas.
There were no arrests.
Senate President David Mark shut down the assembly after the disruption.
"After due consultation with my colleagues in both chambers of the National Assembly on this ugly development we have therefore agreed that today's session be suspended forthwith," Mark said, adding that the assembly will reconvene on Tuesday.
Nigeria's police said in a statement it deployed security only after it received a tip that parliament was about to be invaded by "hoodlums and thugs".
"In the course of this lawful exercise, Aminu Tambuwal, arrived the venue with a motley crowd, who broke the cordon, assaulted the police and evaded due process," it said, adding that police had a duty to restore order.
Nigeria, Africa's top oil producer, is battling a currency crisis exacerbated by falling global oil prices, as well as an Islamist insurgency in three northeastern states.
The February 2015 election is expected to be messy and closely fought.
Jonathan, 58, announced last week that he will seek a second term.
The APC has yet to choose a challenger.
Tambuwal was seen as a potential APC candidate in an already crowded field that includes former President Muhammadu Buhari and former vice-president Atiku Abubakar.
However, Tambuwal said on Tuesday that he would not contest the race.