Police fired tear gas and activities have been suspended this morning in Nigeria’s parliament after Speaker of the House Aminu Tambuwal attempted to scale a security fence at the National Assembly, the BBC reports.

Tambuwal and hundreds of supporters stormed the gate and overpowered security guards who tried to stop the speaker from entering the West African nation’s parliamentary house. Tambuwal had been banned from the National Assembly. He climbed over the fence after first attempting to drive inside and then attempting a second time to gain entry on foot, according to reports from AllAfrica.com.

The leader of Nigeria’s senate, David Mark, ordered the immediate closure of the National Assembly following the incident. A number of other lawmakers, mainly from the All Progressives Congress (APC), the primary rival of Nigerian President Goodluck Jonathan, were also stopped from driving through the second gate. At least 15 of them reportedly tried to scale the fence to gain access to the building as well.

“The speaker reconvene [sic] the House at the instance of the President who wrote a letter to the Speaker asking for an extension of the state of emergency in three states and now he is being ambushed and not allowed in, it is a sad development for our country,” said Lai Mohammed, a spokesman for the APC. “There must be limit to impunity and we are being ridiculed in the eyes of the world.”

Nigeria has declared a state of emergency in multiple states as a result of ongoing attacks by terrorist organization Boko Haram, which is pushing for an extension of the Islamic state. The violence has resulted in the displacement of more than 1.5 million Nigerians, according to the U.N. The number of people displaced inside the country has jumped from 600,000 to around 1.5 million in just the past six months, a U.N. official has said. Tambuwal was lobbying for an extension of the state of emergency declaration when he was banned from the National Assembly.

More than 13,000 people have been killed since Boko Haram began its onslaught in 2009, and the group is said to be in control of more than 20 towns in Nigeria in its quest for a hard-line Islamic state, Agence France-Presse reports.

The APC was formed last year as an alliance by Nigeria's four largest opposition parties to take on the ruling People's Democratic Party.