The Malian army is carrying out a purge of soldiers involved in protests at a barracks outside the capital Bamako last month, Amnesty International said Wednesday.

The rights group's French branch said in a statement that four soldiers' bodies had been discovered near Bamako in early October and several other troops, including a colonel, were missing, feared dead.

Militants killed two Chadian soldiers and a civilian in northern Mali on Wednesday, military sources told Agence France Presse, with Islamist violence escalating in the troubled west African nation.

The ambush follows an urgent request by the United Nations for more troops as its peacekeeping force faces an upsurge in rocket attacks and bombings by militants ahead of nationwide elections.

The president of west African bloc ECOWAS urged member states and other countries on Wednesday to send troops to bolster the United Nations peacekeeping mission in Mali following a surge in Islamist attacks.

Kadre Desire Ouedraogo, speaking two days ahead of a summit in Dakar on the region's economy and recent political crises, called for a positive response to a U.N. appeal launched in New York last week for troop reinforcements and much-needed equipment.

Malian President Ibrahim Boubacar Keita said Monday his country would respond to the "frustrations of our Tuareg brothers" as he opened a conference on devolving power to the west African nation's disaffected ethnic minorities.

Around 600 delegates - mainly central and regional government officials - are taking part in the meeting, part of a plan to broker peace with the restive north after it was occupied by Tuareg separatists following a military coup last year.

The Netherlands is considering sending some 400 soldiers including elite commandos, as well as Apache attack helicopters to war-torn Mali following an appeal for more U.N. peacekeepers, a newspaper report said Saturday.

The plan follows an urgent request by the U.N.'s special representative in the west African country for more blue helmets as its peacekeeping force faced a new surge of Islamist attacks.

France will maintain around 2,000 troops in Mali to help secure the December legislative polls before further scaling down its military presence, the defense minister said Thursday.

"We're going keep a little more than 2,000 men until the end of the year," Jean-Yves Le Drian said.

The head of the EU electoral observer team in Mali said Thursday he hoped a parliamentary poll next month would match the "success" of August's presidential election.

Mali will on November 24 hold its first parliamentary elections since a military coup last year which led to a sweeping Islamist occupation and a French-led military intervention.

The United Nations on Wednesday appealed for extra troops for its Mali peacekeeping force which faces a new surge in Islamist attacks.

U.N. special representative to Mali, Bert Koenders, said recent attacks in the north of the country had been "an important wake-up call" over security.

Amadou Sanogo, who led a March 2012 coup in Mali, has left the army barracks where he lived to move into a new residence in the capital, defense officials said Monday.

"It was necessary for the country's peace of mind that he leave Kati," a garrison town north of the capital Bamako where his headquarters were located, a defense ministry official said.

Twenty people died, including 15 young children, when a boat on the Niger river broke up overnight near the central Malian city of Mopti, officials said Saturday, adding that another 23 people were missing.

"We don't know yet why the boat broke up," Commander Dramane Diallo, from the rescue services, told AFP.