UN and Democratic Republic of Congo government troops have bombarded rebel positions in the country's strife-torn eastern region of North-Kivu.
Three helicopters belonging to the United Nations DR Congo mission - MONUSCO - and two gunships of the DR Congo army (FARDC) were seen and explosions were heard around the villages of Nkokwe and Bukima, where rebels from the M23 group are thought to have some positions.
Officials from the UN and the army confirmed attacks were underway, as did the mutineers.
"The FARDC are currently attacking our positions, but they don't know where we are. There's no problems," a colonel from the mutiny told AFP.
Nkokwe and Bukima are about 50 kilometres (30 miles) north of the Nord-Kivu capital Goma.
The deployment came on Thursday as Ban Ki-moon, the UN chief, urged the presidents of DR Congo and its rival Rwanda to "defuse tensions" over the rebellion.
The rebels, who have seized a number of towns along the Ugandan border, denied plans to advance on Goma, the AFP news agency reported.
Barnabe Kikaya Bin Karubi, DRC's ambassador to Britain, told Al Jazeera that his country was trying to "give peace a chance" and that an emergency meeting bringing together foreign and defence ministers from the Great Lakes region had been called by Uganda to resolve the crisis.
Call for an new military force
The DRC, Rwanda and neighbouring states called on Thursday for the creation of an international military force to eliminate armed rebels in the DRC's turbulent east.
Their agreement, signed on the sidelines of an African Union summit in Addis Ababa, Ethiopia, proposes an internationally-backed military response to an offensive by rebels in the DRC's North Kivu province, a political and ethnic tinderbox.
The document was signed by the foreign ministers of nearly a dozen states of the Great Lakes region, made up of Burundi, DRC, Rwanda and Uganda, and condemned recent advances by the M23 rebel movement and a rebellion by predominantly Hutu fighters of the FDLR insurgent group in North and South Kivu.
It was not immediately clear in the text, to be presented to African heads of state at the Addis summit, where the troops
would come from to establish the "neutral international force" that would take on the Congolese rebel groups.
Eastern Congo's enduring conflict, which has killed, maimed and displaced several million civilians over nearly two decades, has its roots in Tutsi-Hutu ethnic and political enmities dating back to the 1994 Rwandan genocide.
Later invasions of Congo by Rwandan forces and Kigali's backing of Congolese rebels fuelled two crippling wars.
The DRC often refers to its neighbour, Rawanda, as the source of the current conflict.
Ambassador Karubi insisted Rwanda was backing M23 rebels, who take their name from the March 23, 2009, peace agreement they signed with the Congolese government, paving the way for them to be integrated in the national army.
They had previously belonged to the National Congress for the Defence of People (CNDP).
"The United Nations group of experts came up with a report saying there's no rebellion in eastern Congo. It's ... Rwanda which attacked the Democratic Republic of Congo. Rather than focus on M23, let's talk about CNDP which was integrated in the political system [and] in the army," Karubi said.
"Since 1998 we did say the same thing but Rwanda denied. It was under the pressure of the international community that they accepted that they were in Congo. Today it is exactly the same scenario. We have evidence; we can prove it [and] we've been joined by the United Nations."
Rwanda has denied accusations it is supporting M23 rebels, who split from the government army in March in protest at wages and conditions and have been fighting ever since.
Karubi, however, told Al Jazeera that the rebellion started when the DRC government tried to arrest rebel commander Bosco Ntaganda, who served in the CNDP, for war crimes and crimes against humanity.
Ntaganda, nicknamed "terminator" in his home region, had been made a general in the Congolese army following the March 2009 agreement.
UN officials and the DR Congo government fear that M23, which has added fighters in recent weeks, might be planning to target Goma.
But a diplomat in Kinshasa said this now appeared unlikely.
"Everything in the way that the mutineers have withdrawn from Rutshuru indicates that they don't intend to take big towns like Goma," the diplomat said on condition of anonymity.
To try to resolve the crisis Ban this week spoke to Rwanda’s president, Paul Kagame, and his Congolese counterpart, Joseph Kabila, UN spokesman Martin Nesirky said.
Ban "expressed grave concern" over reports that the M23 "are receiving external support and are well-trained, armed and equipped", said Nesirky.
The UN's mission in DR Congo, MONUSCO, is one of the largest UN peacekeeping operations in the world.
It is stationed in the country's east, which has remained unstable since 1997 when Kabila's father waged a guerrilla campaign that toppled Mobutu Seseko's government.
Neighbouring Uganda also warned that fighting between the rebels and Congolese troops risked destabilising the wider region.
Hundreds of thousands of people, including government troops, have fled fighting into Uganda in the past few weeks.
"The crises and conflicts affecting eastern DRC can rapidly destabilise the country and also spread even to the entire region," the Ugandan foreign ministry said in a statement.
"The armed conflict in eastern DRC has increased forced displacement of populations."