Nigeria's Boko Haram puts Maiduguri under 'siege'
Nigeria's militant Islamists have "completely surrounded" Maiduguri, the main city in north-eastern Borno state, traditional elders have warned.
The military needed to "fortify" the city, which had a population of more than two million, to prevent an assault "from all directions", they said.
The Boko Haram militants had "annexed" areas that were about 50km (30 miles) from Maiduguri, they said.
Boko Haram declared a caliphate in areas it controls last month.
Without mentioning the statement issued by the Borno Elders Forum (BEF), the defence ministry has dismissed "alarmist" reports on Maiduguri.
On its Twitter account, it said "Security Arrangements for the Defence of Maiduguri has been upgraded to handle any planned attack".
The BEF represents influential people in the state, including former government ministers and civil servants.
Boko Haram has also captured territory in neighbouring Adamawa state, forcing people to flee into hills, where they are eating leaves, residents told the BBC.
"We are convinced that the Federal Government of Nigeria has not shown sufficient political will to fight Boko Haram and rescue us from the clutches of the insurgents which may ultimately lead to the total annihilation of the inhabitants of Borno," BEF said.
"The insurgents have rendered impassable almost all the roads leading to Maiduguri," it added.
BEF said the military needed to "urgently fortify" the city, where Boko Haram was founded in 2002.
"The insurgents have surrounded Maiduguri and are nursing the ambition of attacking the city from all directions," BEF said.
The BBC's Bashir Sa'ad Abdullahi in the capital, Abuja, says tens of thousands of people are taking refuge in Maiduguri after fleeing Boko Haram's advance.
It is unclear what is happening in territory under their control in Borno, as the mobile telephone network in many places is down, he says.
In Adamawa, the military has launched an air and ground assault to recapture the town of Michika, seized by Boko Haram on Sunday.
Who are Boko Haram?
- Founded in 2002
- Initially focused on opposing Western education - Boko Haram means "Western education is forbidden" in the Hausa language
- Launched military operations in 2009 to create an Islamic state
- Thousands killed, mostly in north-eastern Nigeria - but also attacks on police and UN headquarters in capital, Abuja
- Some three million people affected
- Declared terrorist group by US in 2013
Residents said people in Michika were trapped between the bombs of the Nigerian air force and the militants who shoot anyone that dares move, at times slitting their throats.
One woman told the BBC many children were trapped in her house and had no idea where their parents were.
A man said seven people had died where he was sheltering and they could not be buried.
Michika has a population of about 700,000, and is the gateway to Adamawa's commercial hub, Mubi.
Boko Haram's five-year insurgency is seen as the biggest threat to Nigeria's territorial integrity since the 1967-70 civil war, analysts say.
The group has changed tactics in recent months, holding on to towns in the north-east, where most people are Muslims, rather than carrying out hit-and-run attacks.