The Democratic Republic of Congo deployed two warplanes against advancing M23 militants on Thursday in the country's volatile east, sources said, after a regional bloc called for rebels to disarm.
Tanks and two fighter jets targeted rebel positions in the town of Kibumba at noon, according to a resident who spoke to AFP via telephone from the region's main city Goma.
M23 fighters recently captured the town in North Kivu province, which lies just 20 kilometres (12 miles) north of Goma, a commercial hub of one million people.
A security official, who requested anonymity, confirmed the warplane strikes. "We have hope, we are moving forward," he told AFP.
The retaliation by Congolese forces comes as the M23 has been pushing closer towards Goma, sparking fears of an attack on the city.
Drawn mostly from Congolese Tutsis, the rebel group has recently captured swathes of territory across North Kivu.
The advance has triggered a humanitarian crisis and a showdown with Rwanda -- which the DRC accuses of backing the M23.
Local residents and administrative officials told AFP that the M23 has also begun a push westwards into North Kivu's Masisi territory, from its stronghold near the border with Uganda and Rwanda.
"The rebels are here," a resident of Tongo, a town lying on the road leading to Masisi territory, said on Thursday.
An official in the local administration, who requested anonymity, also told AFP late Wednesday that M23 fighters had entered his office.
The DRC's army has yet to communicate officially about the rebel advance.
Thousands of people marched against the M23 in protests held across the country on Thursday, including more than 15,000 in the capital Kinshasa, according to the organisers.
- Fleeing the enemy -
Thousands of people packed their belongings and headed towards Goma on Tuesday, amid rumours of a rebel advance, after troops were seen fleeing.
The following day, a military tribunal in Goma sentenced three to death for "cowardice" and having "fled before the enemy," among other charges, a court official said.
In practice, the death penalty in the DRC is commuted to life imprisonment.
On Wednesday, the head of the newly created East African Community (EAC) military force in eastern DR Congo, Jeff Nyagah, said that rebels must pursue political negotiations and disarm.
"Those who fail or refuse to voluntarily disarm, then we'll go for them," the Kenyan general warned.
Nyagah also vowed that the EAC force would protect Goma.
Kenya's former president Uhuru Kenyatta, a mediator for the crisis for the seven-nation EAC, had on Tuesday also urged militants to lay down their arms and engage in negotiations.
The EAC has called for a "peace dialogue" in Kenya's capital Nairobi on November 21.
France's foreign ministry on Wednesday condemned the latest violence and urged the M23 to withdraw from its occupied territory, according to a statement.
- Rebel resurgence -
Over 120 armed groups are active across eastern Congo, many of which are a legacy of regional wars that flared at the turn of the century.
The M23 first leapt to prominence in 2012 when it captured Goma, before being driven out and going to ground.
But the rebel group re-emerged late last year, claiming that the DRC had failed to honour a pledge to integrate its fighters into the army, among other grievances.
Despite official denials from Kigali, an unpublished report for the United Nations seen by AFP in August pointed to Rwandan involvement with the M23.
Rwanda accuses Kinshasa of colluding with Hutu militants who fled across the border after the 1994 Rwandan genocide. The DRC denies this.