MAIDUGURI, Nigeria -- Thousands of Nigerians are fleeing a northeastern city amid conflicting reports that it has been seized by Boko Haram Islamic extremists, a federal senator said Tuesday.

The military claims to have repelled the insurgents in fierce fighting but the stream of refugees from the city indicates otherwise, said Sen. Ali Ndume, who is from Borno state.

It would be a major victory for the militants if Boko Haram wins control of Bama, the second largest city in Borno state. That would leave the way open to attack the Borno state capital of Maiduguri that is also the military headquarters of the fight against Boko Haram. Ndume said Bama is 75 kilometres (45 miles) from Maiduguri and has a population of about 200,000 people.

Residents reported Monday that the rebels had taken the military barracks in Bama, but the military said they had fought off the attackers. Sen. Ndume said that was why the air force bungled a bombing raid Tuesday on the barracks, killing an unknown number of soldiers and civilians who had taken shelter there.

Boko Haram has declared an Islamic caliphate in overrun villages in eastern Borno. The group attracted international criticism for its mass kidnapping of more than 200 schoolgirls who remain captive. Boko Haram wants to enforce an Islamic state in all of Nigeria, Africa's most populous nation of some 170 million people divided almost equally between a predominantly Muslim north and mainly Christian south.

The Nigerian government's military-focused campaign against the Islamic militants has failed and its international allies should try to help Nigeria focus on another strategy, said a report released Tuesday by Chatham House, a British institute for international relations.

"The failure of emergency rule to contain and impede Boko Haram violence clearly shows that the military option with an absolute focus on the violent destruction of Boko Haram is not tenable and an alternative must be sought," said the report.

A military state of emergency imposed in May 2013 has alienated ordinary Nigerians while demoralizing and discrediting the armed forces that are accused of gross human rights abuses, said the report.