GENEVA (Reuters) - The United Nations on Tuesday said it was "deeply distressed" by Saudi Arabia's public execution of 10 men, including eight Bangladeshi migrants, and called on the kingdom to stop using the death penalty.

Saudi Arabia said it executed eight Bangladesh nationals on Friday for their part in an armed robbery in which an Egyptian security guard was killed, the state news agency reported.

The U.N. said two Saudi nationals were also executed on the same day for other crimes.

"For eight people to be executed for one murder is a lot of people and that raises questions itself. Ten were executed on the same day, eight of them migrant workers," Rupert Colville, spokesman for the U.N. High Commissioner for Human Rights Navi Pillay, told Reuters.

"The Bangladeshis were beheaded by sword in public."

The U.N. human rights office said it was trying to get more information on the Bangladeshi case, but confirmed that the men had lawyers and contact with their embassy.

"In terms of the whole case, whether it was fairly conducted, we don't really have enough information to make a comment," Colville told journalists earlier.

There were general concerns over whether foreigners received clear interpretation of proceedings in Saudi courts, he said.

Out of at least 58 people believed to have been executed in the OPEC oil giant this year, 20 were migrant workers, he added.

About 140 of the 193 member U.N. states are believed to have abolished the death penalty or introduced a moratorium on executions, he said.

"We call on the Kingdom of Saudi Arabia to join these states and establish a moratorium on the use of the death penalty," he said.

(Reporting by Stephanie Nebehay; Editing by Andrew Heavens)