Government forces will step up their offensive against M23 rebels, already reeling from setbacks in the ongoing conflict in eastern Democratic Republic of Congo (DRC), according to an army officer.
The officer, who declined to be identified as he was not authorised to speak to the media, said on Tuesday a planned attack would take place soon, according to the AFP news agency.
M23 have been pushed to their mountain holdout in the east near the border with Uganda after four days of fighting.
An officer from MONUSCO, the UN mission in the DRC, said Congolese troops were in the process of "reorganising, replenishing supplies and fine-tuning plans".
After 36 hours of silence, the M23 published a statement on their website saying that the withdrawal was "in no way a sign of weakness", but a tactical retreat to Bunagana, the base of its political leaders.
Bunagana is one of the towns in eastern Congo plagued by violence. The main town and previously a target for the rebels to gain control of is Goma, capital of North Kivu province.
M23, so-called after a peace agreement they signed with the government on March 22 2009 before staging a mutiny in April 2012, resumed fighting after the collapse of peace talks in the Ugandan capital Kampala.
The talks followed a ceasefire which took effect in November and saw calm returning to the county's mineral-rich eastern region, where rebels and a motley of militias have battled for control of natural resources for years.
After four days of fierce combat, Martin Kobler, head of MONUSCO in the DRC, reported to the UN Security Council that "practically all M23 positions were abandoned, except for a small triangle at the Rwandan border".
Troops from Tanzania, Malawi and South Africa have been fighting alongside the Congolese army after being granted a special Security Council mandate to take the offensive against armed movements in eastern DRC.
But experts familiar with the conflict in the region said M23 still had the capacity to reorganise and launch a new offensive.
Fidel Bafilemba, a researcher for the US non-governmental organisation Enough Project, said that M23 was "capable of many surprises, even if it is pushed back beyond the borders".
DRC and the UN both accuse Rwanda and Uganda of supporting the M23, allegations that are strongly denied in Kigali and Kampala.
The past few days of renewed fighting has led to international calls for restraint in a country beset by successive civil wars and where hundreds of thousands have been forced from their homes by the rebellion in the east.