Two people were killed, including a teenage girl, and 14 wounded when a bomb exploded yesterday in a Roman Catholic church packed with worshippers on the outskirts of the Nepalese capital, police said.

A Christian leader said the attack, the first on a Christian church, marked the "saddest day" in the history of the religion in the impoverished mountain nation.

The church - Kathmandu's only Roman Catholic place of worship - was packed with around 500 people when the device went off at the start of morning Mass, creating panic as people rushed for the exits, police said.

A pamphlet of an obscure Hindu extremist group called the National Defence Army was found at the blast site in Lalitpur, a district adjoining Kathmandu, police said.

But police said it was too soon to assign blame for the attack on the Church of Assumption which came hours before lawmakers were due to vote in a new premier after weeks of political instability in the world's newest republic.

"A 15-year old student, Celestina Joseph, and 30-year-old Pabitra Paitri died in the bomb blast. Five of the injured are in serious condition," police officer Ram Brish Chaudhary told AFP.

"Security has been increased and an investigation is going on," said Mr Chaudhary.

It was the first attack on a Christian church in the Hindu-dominated Nepal.

"There was a black plastic bag on one of the seats. It blew up when one of the church attendants tried to remove it," worshipper Peter Limbu told AFP from his hospital bed as doctors attended him.

"Suddenly there was a loud noise and flames inside the hall. It was just a few metres away from me," said Mr Limbu, his face and shirt streaked with blood.

"The windows of the church were shattered and there was a panic. All the people began to run outside. I ran for cover too and I can't hear with my right ear now," he added.