UNITED NATIONS (AP) — Congolese and U.N. troops have pushed back the M23 rebel group that had been entrenched in the hills above Goma and the rebels no longer pose a threat to the strategically important city in eastern Congo, the U.N. peacekeeping chief said Thursday.

Herve Ladsous called the military action a "very significant achievement" that inflicted casualties on the M23 and likely led the rebels to resume talks with the government in neighboring Uganda's capital, Kampala.

Late last month, Congolese troops exchanged heavy fire with the M23 rebels just outside Goma. Aided by U.N. peacekeeping troops and the new U.N. intervention brigade, they pounded rebel positions with combat helicopters and reclaimed several areas that had been occupied by the M23 until the rebels unexpectedly declared a cease-fire, saying they wanted to resume talks.

As a result, Ladsous said, "the M23 group has been pushed back towards the north to such a place that it does not any more pose the direct threat that it had posed for such a long time either on the city of Goma" or surrounding camps for displaced people or U.N. positions.

The M23 is primarily made up of fighters from a now-defunct rebel group that signed a peace agreement with Congo on March 23, 2009. The deal paved the way for the rebels to join the regular Congolese military. For the next three years Congo enjoyed a relative period of calm in its troubled and lawless eastern province.

However many defected in 2012, claiming Congo had not held up its end of the bargain by failing to implement the signed agreement. Rebels invaded and briefly held Goma before retreating to positions just outside the city.

Ladsous said following the recent military action the U.N. has strengthened its positions to better defend Goma and the population which had been very critical of the U.N. force is now expressing gratitude for pushing back the M23 fighters.

The international community, bolstered by several reports by the U.N. group of experts, has accused Rwanda of backing the M23, using it as a proxy force to secure access to eastern Congo's lucrative mining trade.

Rwanda signed on to an 11-nation peace deal in February aimed at ending decades of conflict in Congo.

Ladsous said "diplomacy has become again the order of the day."

Special envoys from the U.N., the European Union, the African Union and the United States spent last week traveling around the Great Lakes region and attending a summit of the region's leaders, urging M23 leaders to halt all military action, he said.

Ladsous said there is widespread support for the resumption of talks between the M23 and the government.