Rwanda-backed M23 rebels pressed on with their offensive in eastern DR Congo a day after the Congolese and Rwandan presidents called for an immediate ceasefire, entering the outskirts of the town Walikale late on Wednesday, residents told Reuters.

Gunfire was ringing out from near the town's Nyabanzi neighbourhood, said Walikale resident Janvier Kabutwa.

An army source, who asked not to be named, said the rebels were facing resistance from pro-government militias around the town after overrunning Congolese troops.

Walikale, which is in an area rich in minerals including tin, is the farthest west M23 has reached during its unprecedented advance this year.

Tshisekedi, Kagame meet in Qatar

It sits about 125 km (80 miles) northwest of eastern Democratic Republic of Congo's largest city Goma, which the rebels seized in January.

Alphamin Resources said last Thursday that it was temporarily halting its Bisie tin mine located about 60 km northwest of Walikale town because of the rebel advance.

On Tuesday, DR Congo President Felix Tshisekedi and his Rwandan counterpart Paul Kagame met in Qatar for their first direct talks since M23 stepped up its offensive in January.

They issued a joint statement along with Qatar that called for an "immediate and unconditional" ceasefire.