The Congolese army is said to badly need discipline
The military chief of staff in the Democratic Republic of Congo has been sacked after the army lost territory to rebel forces in the east.
The reason for Dieudonne Kayembe's dismissal was the urgency of the conflict, a TV statement said.
President Joseph Kabila named navy chief General Didier Etumba Longomba as the new head of the armed forces.
Meanwhile, a UN peacekeeping commander says he cannot defeat the rebels because of his rules of engagement.
General Bipin Rawat, who commands 6,000 troops, told the UK's Daily Telegraph newspaper that his forces were denied any element of surprise by having to go into the jungle with white trucks and white armoured vehicles.
UN troops also have to fire warning shots and shout verbal warnings before engaging the rebels.
Earlier, France presented a draft resolution to the UN Security Council to strengthen the UN force in DR Congo.
At present, there are about 17,000 soldiers and police in DR Congo - the biggest UN force of its kind.
The move - to be voted on next week - would increase the number of UN troops in the country by 3,000.
Clashes between the army and the rebel forces of renegade General Laurent Nkunda have driven hundreds of thousands of people from their homes and created a humanitarian crisis.
Correspondents say General Longomba takes responsibility for a badly paid force with low morale and will need to instil discipline.
The BBC African Service's Kassim Kayira says the army shares the blame for atrocities against the population it is meant to be protecting.
As they have retreated from Gen Nkunda's fighters in recent days, army soldiers looted shops and homes and raped women.
A military tribunal on Monday sentenced four soldiers to life in prison for rape, looting and deserting their posts, according to the AFP news agency.
FORCES AROUND GOMA
CNDP: Gen Nkunda's Tutsi rebels - 6,000 fighters
FDLR: Rwandan Hutus - 6-7,000
Mai Mai: pro-government militia - 3,500
Monuc: UN peacekeepers - 6,000 in North Kivu, including about 1,000 in Goma (17,000 nationwide)
DRC army - 90,000 (nationwide)
Source: UN, military experts
In the latest violence, the rebels are reported to have taken the town of Rwindi, about 125km (75 miles) north of Goma.
The fighting comes as UN envoy Olusegun Obasanjo continues efforts to broker an end to the conflict.
In talks with Mr Obasanjo on Sunday, Gen Nkunda said he would support a peace process with the government.
He also agreed to ceasefire monitors being deployed, as long as they did not include UN peacekeepers, whom he accuses of bias.
The government of President Kabila has to date rejected rebel calls for direct negotiation.
An estimated 250,000 people have been made homeless by weeks of fighting between rebels and government troops.
Gen Nkunda says he is fighting to protect his Tutsi community from attacks by Rwandan FDLR Hutu rebels who fled to DR Congo after the 1994 genocide.
The Congolese army has been accused of working with the FDLR fighters to exploit eastern DR Congo's rich mineral resources.
The DR Congo government says Gen Nkunda is backed by neighbouring Rwanda - charges denied by Rwanda's government.