Kano, Nigeria (CNN) Hundreds of Boko Haram gunmen on Sunday launched a predawn attack on the Nigerian city of Maiduguri and were locked in a fierce battle with government troops on the outskirts of the city, according to the military, residents and citizen vigilantes.

The militants launched a simultaneous attack on the town of Monguno and were apparently successful in taking control of the town and its military barracks, a Nigerian military officer in Maiduguri told CNN.

"Our soldiers initially repelled the terrorists but they mobilized more fighters and came back in full force. They overwhelmed our troops and forced them to retreat," said the officer, who asked not to be named because he was not authorized to speak to the media.

Monguno, a town of about 100,000 people in northeast Nigeria, is about a 135-kilometer (85-mile) drive from Maiduguri, a city of more than 600,000. Both cities are tucked into the corner of the country, near the borders with Chad and Cameroon.

Babagana Musa, a Monguno resident who fled to Maiduguri, said, "Several trucks carrying soldiers drove into Maiduguri. We learned the town (Monguno) has been taken over by Boko Haram."

Monguno, with its huge military barracks, has a strategic importance ‎in that it acts as a buffer to keep Boko Haram from advancing towards Maiduguri. Its fall means Boko Haram is in good position to advance on Maiduguri, which has been its goal for months.

Boko Haram had been confined to the fishing town of Baga since its fighters seized it January 3, hesitant to move south towards Maiduguri because of the military presence in Monguno.

The Islamists attacked the nearby village of Jintilo around 5 a.m. and were engaged in a gunbattle with troops stationed there. The village is about 5 kilometers (3 miles) from the center of Maiduguri, the capital of Borno state.

Speaking to reporters Sunday afternoon, Borno Governor Kashim Shettima said, "So long as we have the resources, we will continue to regard the efforts to reclaim peace our No. 1 area of commitments. I want to reassure the good people of Borno State that we will never abdicate from our responsibility as those they entrusted with leadership."

He further said he had canceled all engagements outside of Borno and intends to "remain behind with our people through thick and thin," and after meeting with other past and present leaders in Northern Nigeria, "pressures are being combined and channeled to the right authorities to ensure that the insurgency problems are brought to an end as quickly as possible."

Shettima closed by asking the people of Borno to remain "optimistic and vigilant" and urged residents to keep close watch over their children and report any "strange person and movement" to authorities.

The Islamists attacked the nearby village of Jintilo around 5 a.m. and were engaged in a gunbattle with troops stationed there. The village is about 5 kilometers (3 miles) from the center of Maiduguri, the capital of Borno state.

The fighting in Jintilo forced residents to evacuate their homes and flee into the city, while military authorities imposed a round-the-clock curfew to prevent infiltration by the militants.

"All the residents of neighborhoods near Jintilo have fled into the city due to the ongoing battle between troops and Boko Haram gunmen who want to enter the city," said Modu Zannari, who lives nearby.

"Boko Haram gunmen in their hundreds attacked Jintilo around 5 a.m., just before the morning prayers, but soldiers stationed there fought back," Zannari said

"Since 5 a.m. all we hear are cracking of guns and booming explosions coming from the direction of Jintilo," said Babakaka Said, a resident of another neighborhood near the scene of the fighting.

"There have been radio announcements of indefinite curfew in the city and we have all been asked to remain indoors," said Adam Kolo‎, who lives in the heart of the city.

Hundreds of troop reinforcements deployed in Jintilo and military jets carried out aerial bombardment of Boko Haram positions, said a member of a civilian vigilante group fighting Boko Haram alongside troops.

"The ‎gunmen have been dealt with and are now on the run, but they are being pursued by soldiers and vigilantes with the aerial support of a military jet," said the vigilante, who asked not to be named because he was not authorized to speak on the incident.

The attack came a day after President Goodluck Jonathan made a campaign stop in Maiduguri ahead of the February 14 presidential election. He has promised to end the Boko Haram insurgency if re-elected.

On Friday, Boko Haram attacked Kambari village, 5 kilometers from Maiduguri, killing 15 people and burning homes, in what was seen as a prelude to a possible onslaught on the city.

Also Friday, Boko Haram released 192 hostages, mostly women, who had been kidnapped from a village in Yobe state following a deadly raid, according to community leaders, a local politician and a military source.

The hostages had been held in two Boko Haram enclaves since a January 6 raid on the village of Katarko, 20 kilometers from the state capital, Damaturu, in which 218 women and children were abducted, according to sources.

"Boko Haram have returned to us our 192 women they took away at the beginning of this month‎. They freed them on Friday and dropped them at Girbuwa (village) near Damaturu," Diptcha Aisami, a community leader in Katarko, said.

The hostages were released after they declined to fight alongside Boko Haram, which branded them infidels, said a local politician from Katarko.

"They (Boko Haram) are still holding 26 young boys they abducted along with the released hostages in Katarko," said the politician, who asked not to be named for security reasons.

A military officer confirmed the release of the hostages by Boko Haram.‎

On January 6, dozens of Boko Haram gunmen stormed Katarko, where they killed 25 men and threw the bodies in open wells, burned the entire village and kidnapped the women and children, according to Aisami and local vigilantes.

The attack was apparently in reprisal for a raid on a Boko Haram enclave by local hunters and vigilantes in Buni Yadi, 20 kilometers away, hours earlier. Several Boko Haram fighters were killed in that raid; scores of others were arrested and an arsenal was seized, according to vigilantes.