(Expands with quotes from Deng)

By Patrick Worsnip

UNITED NATIONS, Jan 29 (Reuters) - The U.N. special adviser on preventing genocide and mass atrocities on Tuesday warned leaders responsible for post-election violence in Kenya they could be held to account for violations of international law.

Francis Deng told Reuters he was sending a staff member to look into the situation in the east African country, where around 850 people have been killed since the disputed re-election of President Mwai Kibaki in December.

The official, Marylene Smeets, was due to leave on Thursday, Deng said in a telephone interview.

Deng said he was not saying that anything that had happened so far in Kenya amounted to genocide. "We're not talking the g-word at this point, but the kind of atrocities we're seeing could easily escalate to dangerous levels," he said.

"Our whole approach is preventive," Deng said. "It's a question of letting people know that someone has a role to play in instigating or potentially preventing the violence. There is always that prospect of someone being held accountable."

Deng said those responsible would initially be answerable under domestic law but if they violated international law, their accountability would be "at different levels". He declined to say what international body might take action.

Deng said Smeets' mission would be to gather information and report back to him so that he could brief U.N. Secretary-General Ban Ki-moon.

Separately, Deputy U.S. Ambassador to the United Nations Alejandro Wolff said he raised the issue of Kenya at a meeting of the U.N. Security Council on Tuesday.

"We think this is a tragic situation," Wolff told reporters. "And we thought it was high time that the council hear from the (U.N.) secretariat and get a full briefing on the situation on the ground."

Ban's predecessor, Kofi Annan, is in Kenya and on Tuesday brought the country's political rivals together in a push to end the crisis and deepening tribal bloodshed.

The United Nations has smarted from accusations that it failed to prevent genocide in Rwanda in 1994 but has suffered from the lack of an agreed definition of the term.

When Deng was appointed last year, Ban told the Security Council the job title had been changed "by adding 'mass atrocities' to make it broader in scope without the need to determine first whether a specific situation has a 'genocidal' character or not." (Editing by Cynthia Osterman)

AlertNet news is provided by