Amid new tensions over Western Sahara, a U.N. envoy said Wednesday there was still no hope of convening face-to-face talks on the disputed territory between Morocco and pro-independence rebels.

Morocco, which occupies the territory, recalled its ambassador to Algiers as the U.N. Security Council held talks on Western Sahara. Algeria is a key backer of the Polisario Front independence movement.

The U.N.'s refugee agency on Tuesday urged Cameroon and other nations not to expel Nigerians who have fled their homes amid fighting between Boko Haram Islamist rebels and government troops.

"With the recent escalation of violence in northeast Nigeria, UNHCR is today advising all states against forced returns of people to the region," spokesman Dan McNorton told reporters.

Thirty-five bodies in military uniform have been brought to a morgue in Nigeria's restive northeast after a coordinated assault by Boko Haram targeting the security forces, a hospital source told Agence France Presse Monday.

The attack late Thursday in the Yobe state capital of Damaturu was the first raid in a major urban center in several weeks by the insurgent group waging a four-year Islamist uprising.

Nigeria's army said Friday it had killed 74 suspected Boko Haram fighters in a raid in northeastern Borno state, as gunmen from the Islamist group battled security forces in a neighboring area.

The army, which is battling to crush a four-year Islamist uprising in Nigeria, said it deployed bombs and ground troops to destroy insurgent camps in Borno on Thursday.

Suspected Boko Haram Islamists attacked police in the northeast Nigerian city of Damaturu, prompting a fierce gunfight with troops, a police officer and residents said Friday.

The gunmen late Thursday stormed the city in coordinated raids, burning at least four police buildings and leaving an unspecified number of casualties, said a senior police officer, who requested anonymity.

Cholera has killed nine people and infected 100 others this month in Namu village in Nigeria's central Plateau state, a senior health official said Wednesday.

"Over 96 persons have been infected by cholera and hospitalized... while nine persons have lost their lives as a result of the outbreak of the disease," state epidemiologist, Raymond Yuryit, told journalists.

Nigeria's military said Tuesday it killed 37 suspected Boko Haram fighters in a ground and air assault on an insurgent camp in the northeast, the epicenter of the Islamist group's four-year uprising.

The military attacked a suspected Boko Haram camp in Borno state, said military spokesman Aliyu Danja.

Boko Haram gunmen dressed in military uniform on Sunday killed 19 people near the Nigerian border with Cameroon in the restive northeast where the Islamists have carried out deadly attacks, residents and a survivor said.

The motorcycle-riding gunmen armed with Kalashnikovs blocked the highway near the town of Logumani, 30 kilometers (19 miles) from the border, shooting and hacking to death 19 motorists and burning three trucks, they said.

Nigeria's military said Tuesday it repelled coordinated attacks by Boko Haram Islamists at the weekend, killing 40 insurgents, but few details were provided and the account could not be independently verified.

According to a military statement, Islamist fighters "of unknown strength attempted coordinated and simultaneous attacks" on Sunday in three remote towns in northeastern Borno state, Boko Haram's historic stronghold.

Rights group Amnesty International on Monday called for an urgent investigation after saying it had evidence that hundreds of people had died in detention facilities during a crackdown on Islamists in Nigeria.

The group said prisoners had been suffocated, starved and subjected to extra-judicial killings in the army-led operation in the country's north east.