Clashes have erupted between fighters loyal to rebel leader Laurent Nkunda and the army in the east of Democratic Republic of Congo, the UN says. Both sides have blamed each other for starting the fighting, which lasted several hours. The UN mission told the BBC 18 rebels had been admitted to hospital, while AFP news agency said 50 government soldiers were also receiving treatment. It is the heaviest fighting in the east since a January peace deal. Earlier this month, US and European Union diplomats warned that the situation in eastern DR Congo was becoming increasingly tense and that all sides were rearming. Human rights groups said that tens of thousands of people were fleeing as the situation in the area deteriorated. 'Want dialogue' "They are mutually claiming the other side started it. At the moment it's very difficult to confirm who has started it," UN mission spokesman Lieutenant-Colonel Jean Paul Dietrich told the BBC. Rebel spokesman Rene Abandi said the fighting had started in the early hours of Thursday morning around Rutshuru, 50km (31 miles) north of the city of Goma. He said there had been several skirmishes with the army over the last week in Masisi and Rutshuru areas of North Kivu province, but denied that the rebels were behind the unrest. The rebels had written to the peace facilitators about the incidents, he said. "We explained that we want dialogue to end this fight," he told the BBC's Focus on Africa programme. At the end of January a peace deal was signed in Goma between the government and the variety of groups. It was supposed to have seen the disarmament of groups and their integration into the army. Mr Abandi said the rebels were not being given enough time to disarm. "It's not true that we're breaking the ceasefire. They're trying to lie because they want war. When they're fighting us, how can we disarm?" he said. Lt-Col Dietrich said the UN believed that Mr Nkunda - a renegade general - was trying to expand the rebels' zone of influence. Reports earlier this month indicated that Gen Nkunda was touring his area, strengthening his defences and recruiting fresh forces. The UN has 17,000 peacekeepers in DR Congo. Source: BBC