The United Nations expressed deep concern at reports of M23 rebels and Rwandan troops advancing south towards the Congolese city of Bukavu on Thursday, as the militants sought also to assert their control over east Congo's largest city Goma.

Much of the beleagured city of Goma was calm early Wednesday morning, after a day during which thousands of fleeing people hunkered down by roadsides as missiles flew and injured people streamed to overwhelmed hospitals.

Residents in eastern Congo’s largest city of Goma are fleeing after Rwanda-backed rebels claimed to have captured the regional hub from Congolese forces.

As an East African bloc urged an immediate ceasefire in eastern Democratic Republic of Congo, Rwandan-backed M23 rebels who seized the city of Goma extended their advance on Wednesday, and Congo said it planned a campaign to recover lost territory.

Residents of Goma reported gunfire and shelling after rebels overran Congolese troops. U.N. officials estimated that more than one million displaced people were now inside the city.

Rwanda-backed rebels claim they have captured eastern Congo’s largest city, Goma, as the United Nations describe a “mass panic” among its 2 million people and Congo’s government say the rebel advance was a “declaration of war.

The United States urged the United Nations Security Council on Tuesday to consider measures to halt an offensive by Rwandan troops and M23 rebel forces in eastern Democratic Republic of Congo as a conflict there escalates.

The Romanian soldiers were contracted by the Democratic Republic of Congo in a bid to stop the rebel advance. View on euronews

By Yassin Kombi and Sonia Rolley GOMA, Democratic Republic of Congo (Reuters) - Rwandan-backed rebels strengthened their control over east Congo's largest city, Goma, on Wednesday as columns of Romanian mercenaries hired to fight for Congo entered Rwanda under tight supervision by Rwandan security forces.