The DRC has been subject to a United Nations arms embargo since 2000, originally imposed over widespread violence in the central African nation.

In 2008, the Security Council amended the sanctions regime to apply only to armed groups. The government must still notify a monitoring committee of arms purchases under the rules, however, which some in the DRC view as a bureaucratic hurdle.

On Thursday, the Security Council prolonged the regime by a year but also reduced the notification requirements for certain weapons purchases.

The move nonetheless triggered outrage in the DRC, where there have been calls to lift the UN restrictions amid a surge of clashes with M23 militia in the east.

The primarily Congolese Tutsi rebel group is one of scores of militias active in eastern DRC. Last month, M23 fighters captured the strategic town of Bunagana on the Congolese-Ugandan border.

Tembos Yotama, a local representative in the eastern North Kivu province, argued that the government should be allowed to purchase weapons with "no conditionality at all".

"When the UN imposes any restriction on the purchase of arms to a country facing a hundred armed groups, it is a way to weaken it further," he said.

However, Mike Mukebayi, a lawmaker in the capital Kinshasa, said the UN decision showed the need to improve the Congolese weapons-monitoring system, which he called "broken" and "obsolete".

Claudel Lubaya, an MP from central DRC, also urged improved weapons monitoring. He said the current disfunction was deliberate, because untraceable weapons "are a source of illicit and rapid enrichment".

Under the UN Security Council resolution passed on Thursday, the DRC's government must notify the monitoring committee of all purchases of mortars, grenade launchers, portable air-defence systems and anti-tank missiles.

The M23 or "March 23 Movement" first leapt to global prominence in 2012 when it briefly captured Goma, an important commercial hub of about a million people in North Kivu.

A joint offensive by UN and Congolese troops drove the rebels out in 2013. But after lying mostly dormant for years, the M23 resumed fighting last November after accusing the government of failing to honour an agreement to incorporate its fighters into the army.

The DRC has accused neighbouring Rwanda of backing the M23, which Kigali has repeatedly denied.