Many Rwandan Catholics believe the Church let them down in 1994

Athanase Seromba had appealed against a 15-year sentence over the deaths of hundreds of Tutsis who had sought refuge in his church.

But the United Nations-backed tribunal decided he was even more closely involved than previously thought.

Father Seromba was the first Catholic priest to face genocide charges at the court, sitting in Arusha in Tanzania.

He had denied charges that he organised the massacre of 1,500 Tutsis at the church in Nyange in the west of Rwanda.

Prosecutors said that after he ordered the church to be demolished by bulldozers, he sent in militiamen to kill any survivors with machetes and guns.

All those inside the building are said to have died.

The appeal judges ruled that his responsibility went beyond helping and encouraging the killings, which is the basis on which he was originally sentenced in December 2006.

Some 800,000 Tutsis and moderate Hutus were slaughtered in the 1994 killings.