By Hereward Holland

GOMA, Congo, Nov 9 (Reuters) - Their church crammed with refugees, thousands of Congolese in the eastern town of Goma prayed outdoors on Sunday for an end to fighting that threatens regional peace.

Dissident Tutsi general Laurent Nkunda's men and Congolese government soldiers and their allies fought in various parts of North Kivu on Sunday despite calls by regional leaders for a ceasefire.

The fighting is hampering aid workers' attempts to help tens of thousands of people who have fled two weeks of clashes that have sparked flurries of regional diplomacy and what the United Nations has called a humanitarian "catastrophe".

"The priest told us we must pray for those who are not ready to let peace come to our country," said Lewis Fariala, a volunteer at the Don Bosco centre in Goma.

"I think it will be impossible to have peace without (these prayers)," he said after a service during which several thousand town residents and displaced villagers, many in bright robes, gathered to sing and clap.

Mass was held on pews in the open air as the centre's Catholic church is home to about 1,000 displaced women and children. Another 2,000 sleep elsewhere but are fed by the centre. A handful of children played football on the black, volcanic earth.

"We only have five litres of water between the seven of us," said 15-year-old Furaha Sebangezi, who fled into Goma and is now living on a plastic sheet. "I couldn't find water ... but I didn't want to go to church without washing."

A summit of South African leaders in Johannesburg called for a ceasefire to allow aid workers to help the displaced, who now number about one million in North Kivu. Pope Benedict urged the end to the violence and "systematic atrocities".

Innocent Kibumba, a refugee at a camp in Kibati, 12 km (7 miles) north of Goma, said: "Help? Help comes but there are others who still haven't found help. We are here but we haven't yet found anything to eat."

After Nkunda declared a ceasefire last week, some aid workers were able to assist refugees in rebel-held territory. But renewed fighting this week has put an end to much of this.

CLASHES ON SEVERAL FRONTS

U.N. peacekeepers said there were clashes on Sunday morning in three parts of North Kivu, where Nkunda has waged his four-year rebellion, before calming down after they intervened.

Nkunda's men fought against government forces and the Mai Mai, a pro-Kinshasa militia, in two clashes north of Rutshuru, and were fighting Rwandan Hutu rebels at Ngungu, 60 km (37 miles) west of Goma, said U.N. military spokesman Lieutenant-Colonel Jean-Paul Dietrich.

Refusing to sign up to the 2003 deal that ended Congo's wider five year war, Nkunda first justified his rebellion saying he was protecting his fellow Tutsis from attacks by Rwandan Hutus, some of whom came to Congo after the 1994 genocide, during which 800,000 Tutsis were killed.

Among other complaints are that Congolese government forces are fighting alongside and not, as promised, disarming the Hutu rebels. But he has since broadened his rebellion and has threatened to take it to the distant capital, Kinshasa.

The fighting has taken on a regional dimension as Rwanda, which has twice invaded Congo, officially to fight the Hutu rebels, is accused of supporting Nkunda. Kinshasa has called on powerhouse Angola, which backed it during the war, for help.

Congo's notoriously weak and chaotic army collapsed during Nkunda's advance last week. But the appearance in North Kivu of more disciplined, Portuguese-speaking soldiers has fuelled speculation Angola has sent reinforcements.

But General Vainqueur Mayala, head of the army in North Kivu, denied the troops came from the former Portuguese colony.

"It is true that some of them speak Portuguese. They have been trained by an Angolan contingent, they spent a lot of time with the Angolans ... I speak French but I am not French," he said. (Writing and additional reporting by David Lewis; Additional reporting by Yves Boussen in Kibati and Emmanuel Braun in Goma; Editing by Daniel Magnowski and Elizabeth Piper)

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