Boko Haram militants have seized the town in north-eastern Nigeria that nearly 300 schoolgirls were kidnapped from in April.
The Islamic extremists entered Chibok, in Borno state, on Thursday evening, forcing thousands of people to flee as they shot from pickup trucks and motorcycles.
"Nobody can tell you what is happening there today because everybody is just trying to escape with their lives," Bana Law chairman of the Chibok local government.
Mixed reports indicate the insurgents appear to have attacked the predominantly Christian enclave after fighting in neighbouring Adamawa state.
“We learnt that the soldiers who were posted in Chibok also ran away as is usual these days,” Senator Ali Ndume of Borno State said.
“They left the villagers behind,” Mr Ndume claimed to the BBC.
Surviving residents described to the Guardian fleeing down streets filled with bodies as Boko Haram swarmed into the town.
Chibok came to international attention after the kidnapping of 276 schoolgirls on 14 April.
A campaign to #BringBackOurGirls went viral on social media with little tangible effect. The majority of the girls taken still remain in captivity after a series of bungled or ineffectual attempts by the Nigerian government.
Boko Haram leader Abubakar Shekau, who declared a caliphate in the areas that he controls, said in video released last month said the girls were "an old story," that they all had converted to Islam and been married off to his fighters.
In pictures: Nigeria kidnapped schoolgirls
In pictures: Nigeria kidnapped schoolgirls
A total of 276 girls were abducted from the northeastern town of Chibok, in Borno state, which has a sizeable Christian community. Some 223 are still missing
One of the kidnapped girls looks into a camera
One of the missing girls talking to the camera
The missing Nigerian schoolgirls, wearing the full-length hijab and praying in an undisclosed rural location. Boko Haram alleging they had converted them to Islam
Girls wearing the full-length hijab holding a flag reading "There is no god, but Allah" and "Mohammed is Allah's prophet"
A man claiming to be the leader of Nigerian Islamist extremist group Boko Haram Abubakar Shekau
Abubakar Shekau speaks on the video
Girls, wearing the full-length hijab and praying are filmed by an unidentified man (R) in an undisclosed rural location
People carry signs as they attend a protest demanding the release of abducted secondary school girls in the remote village of Chibok in Lagos
A protester demonstrates against the kidnapping of school girls in Nigeria, outside the Nigerian Embassy in London
Chief International Correspondent Christiane Amanpour and Prime Minister David Cameron appearing on the BBC1 current affairs programme
People participate in a "Bring Back Our Girls" campaign demonstration and candlelight vigil in Los Angeles
Girls holding heart shaped banners in a "Bring Back Our Girls" campaign demonstration and candlelight vigil in Los Angeles
14/19 South Africa
South Africans protest in solidarity against the abduction of hundreds of schoolgirls in Nigeria by the Muslim extremist group Boko Haram and what protesters said was the failure of the Nigerian government and international community to rescue them, during a march to the Nigerian Consulate in Johannesburg
Karilyn Coates (10) joins others in a candlelight vigil for the more than 300 girls abducted by Boko Haram in Nigeria, at All Souls Unitarian Church in Colorado Springs
Mothers of the missing Chibok school girls abducted by Boko Haram Islamists gather to receive informations from officials. Nigeria's president said that Boko Haram's mass abduction of more than 200 schoolgirls would mark a turning point in the battle against the Islamists, as world powers joined the search to rescue the hostages
Former Nigerian Education Minister and Vice-President of the World Bank's Africa division (3rd L) Obiageli Ezekwesilieze speaks as she leads a march of Nigeria women and mothers of the kidnapped girls of Chibok, calling for their freedom in Abuja
18/19 Bring Back Our Girls
Kelly Hoppen tweeted: 'Please make sure you do this, we must stand together and not forget them'
19/19 Bring Back Our Girls
E.L. Rock Star tweeted: 'Join The Movement'
Many of the parents of the 219 girls who remain under Boko Haram’s control had stayed in the town in the hope their daughters might return.
Tsambido Hosea Abana, a community leader from Chibok whose nieces and cousins are among the captured girls, said to the Guardian: “Our girls are in the bush and they are killing the parents. We are talking about the lives of the parents and adults now. This thing has gone beyond anyone’s control.”
As violence – some would say chaos – escalates heavy criticism has been levelled at leading Nigerian politicians who appear to have done more to bolster their public personas ahead of upcoming elections than to protect individuals under threat from the Islamic militants.
“It should have been obvious to everyone that Boko Haram was going to target Chibok. It shows a lack of compassion, a lack of empathy and a lack of concern," Emman Usman Shehu, an activist with the Bring Back Our Girls campaign, said to AFP.
The news comes as UNHCR released a report that claimed 13,000 people have been forced to flee into neighbouring Cameroon as the extremist Islamists continue their deadly attacks.
Although the report details that many of these people have now returned to central Nigeria, the insurgency continues to displace thousands more as the country broils in a vicious civil conflict which is believed to have affected roughly three million people.
Boko Haram was founded in 2002 and launched military attacks in 2009 to establish a caliphate. It was declared a terrorist group by the US in 2013, and is infamous for its use of Sharia law – publishing theft with amputations for example.
Additional reporting from the AP