United Nations Secretary General Ban Ki-moon has expressed concern about worsening violence in Iraq and where US policy on Iraq might be heading.

He told the BBC that he was making contingency plans in case of a sudden change of direction in American policy.

He said his main concern was ensuring the safety and security of his staff.

Mr Ban's comments come as a new interim report on Iraq is expected in Washington, amid mounting political pressure for troop reductions.

Mr Ban was speaking in London, after talks with the new UK Prime Minister, Gordon Brown.

"I'm not quite sure what kind of a strategy the American government will have," he said.

"But whatever the strategies they may have, I hope that they will have a close consultation."

Mr Ban said the situation in Iraq was a problem for the whole world, and he found the continuing civilian casualties and sectarian violence there deeply troubling.

He said both he and his special envoy in Baghdad had talked it over with the Iraqi leadership, but the safety and security of his staff was a priority.

The secretary general said he expected a different relationship with Mr Brown from the one he had with his predecessor, Tony Blair.

"Different circumstances will require different leadership," he said.

"I am sure that the new administration of the United Kingdom will have a new leadership under new circumstances."

Mr Ban said Mr Brown had agreed to collaborate on climate change, Darfur, and the UN's Development Goals.