On Wednesday, the army said the troops, backed by tanks, mortars and heavy machine guns mounted on gun carriages, pounded M23 positions north of the flashpoint city of Goma, the capital of North Kivu, AFP reported.
Army officials said front-line units had moved forward 300 meters by mid-afternoon.
The rebels appeared to offer little resistance, claiming that the army and the United Nations Organization Stabilization Mission in the Democratic Republic of Congo (MONUSCO) were setting a “trap” for them.
“There’s a risk of drawing MONUSCO (into the conflict). I think that’s the trap that the FARDC (DR Congo army) and MONUSCO want to set for us,” said Bertrand Bisimwa, M23’s political chief.
On Tuesday, Congolese army spokesman Colonel Olivier said that Congo’s forces were gaining ground in the battle near Goma.
However, Colonel Youssouf Boneza, the commander of M23 operations in the area, said, “M23 is holding its positions in spite of heavy shelling.”
On Monday, Congolese government spokesman Lambert Mende said the army had “inflicted very heavy losses on the M23 fighters, 120 have been killed and 12 captured,” while 10 government soldiers were killed in the fighting.
Hundreds of people have been forced to flee their homes since the fighting began on Sunday.
“This recurrence of fighting close to inhabited areas poses a serious protection issue for thousands of people and could trigger some drastic humanitarian consequences,” said Moustapha Soumare, the United Nations humanitarian coordinator in Congo.
The Congolese government said at least 130 people, including 10 soldiers, were killed in Sunday’s fighting.
UN forces in Goma, which have been on high alert, have begun patrols but are not yet engaged in combat.
The United Nations has announced that it is ready to use “lethal force” to protect civilians in Goma if the M23 rebels advance toward the city.
UN peacekeepers “stand ready to take any necessary measures, including the use of lethal force, in order to protect civilians,” MONUSCO said in statement issued on July 15.
The M23 rebels seized Goma on November 20, 2012 after UN peacekeepers gave up the battle for the frontier city, which is home to about one million people. The rebels withdrew from the city on December 1 under a ceasefire accord.
Several armed groups, including the M23 rebels, are active in the eastern Congo and are fighting for control of the country’s vast mineral resources, such as gold, the main tin ore cassiterite, and coltan (columbite-tantalite), which is used to make many electronic devices, including cell phones.
The M23 rebels defected from the Congolese army in April 2012 in protest over alleged mistreatment in the Armed Forces of the Democratic Republic of Congo (FARDC). They had previously been integrated into the Congolese army under a peace deal signed in 2009.
Since early May 2012, more than three million people have fled their homes in the eastern Congo. About 2.5 million have resettled in Congo, but some 500,000 have crossed into neighboring Rwanda and Uganda.
Congo has faced numerous problems over the past few decades, such as grinding poverty, crumbling infrastructure, and a war in the east of the country that has dragged on since 1998 and left over 5.5 million people dead.