The stretched United Nations peacekeeping mission in Congo wants the European Union to send a force of 800 soldiers to help beef up security for elections this year, diplomats said.
The United Nations is also seeking to transfer some of its soldiers from neighbouring Burundi to contain violence in the southern Congolese province of Katanga, where the mission's presence is minimal, a UN spokesman said.
Democratic Republic of Congo hosts the UN's largest and most expensive mission, with nearly 17,000 peacekeepers.
But its troops are thinly spread across the vast central African country and requests for thousands more have been repeatedly turned down.
"We have to keep the pressure on where we have been having results," a senior UN military officer said. "So, instead of pulling soldiers off operations to have a reserve, we want to bring in a reserve EU battalion," the officer added.
The UN peacekeepers have had some success disarming rebels, and the Congo held a referendum on a new constitution last month, its first independent poll in 40 years.
But thousands more rebels remain in the bush, the national army is weak and Congo must hold elections, aimed at ending five years of war, before the end of June.
EU diplomats in Brussels said the EU would consider a UN request for troops.