A Congolese militia group has threatened to order the execution of seven U.N. peacekeepers being held hostage in the Democratic Republic of Congo.

Seven Nepalese U.N. peacekeepers have been held hostage in eastern Congo for more than a month, with little sign of their imminent release.

Specialist negotiators are in place and the local community is working for their release. But, following clashes between militiamen and the Congolese army late last week, a rebel group has issued new threats.

The Revolutionary Movement of Congo, which brought together a series of militia groups to form a loose coalition in the lawless Ituri district, has accused the U.N. and government forces of trying to rescue the hostages.

If another such attempt is carried out, the Revolutionary Movement of Congo would order the execution of the peacekeepers, the group said in a statement.

While taking the threat seriously, U.N. officials are not sure how much authority the Revolutionary Movement of Congo holds over the specific group of gunmen holding the peacekeepers.

A spokesman for the U.N. force in eastern Congo denied any attempt had been made to rescue the peacekeepers and insisted the world body was continuing to try to negotiate their release.

The local militia leader holding the seven blue helmets, Peter Karim, has issued a range of demands, including thousands of dollars in cash and the release of fellow militiamen held by Congo's government.

But the United Nations has called for their immediate and unconditional release.

The hostage crisis highlights persistent insecurity in the Congo, just a month before the former Belgian colony is due to hold elections to draw a line under its violent recent past.