UNITED NATIONS, Nov 5: UN Secretary General Kofi Annan has warned United States that major military campaigns in Iraq's militant strongholds can jeopardize upcoming elections.

In a letter dated Oct 31, Mr Annan told American, British and Iraqi leaders that the United Nations wanted to help prepare for the elections, scheduled for the end of January, but feared a rise in violence could disrupt the process.

"I have in mind not only the risk of increased insurgent violence, but also reports of major military offensives being planned by the multinational force in key localities such as Fallujah," Annan wrote in the letter.

Mr Annan warned that new military assaults, "in which the main burden seems bound to be borne by American forces," might discourage Iraqis from participating in the vote.

The UN chief urged the US-led coalition to give more time for dialogue to succeed and offered UN help. "I, and all my colleagues at the United Nations Secretariat, want to help," Mr Annan wrote. "But we need a conducive environment if elections are to produce a positive effect."

After meeting with European leaders at a European Union summit in Brussels, Iraq's interim Prime Minister Iyad Allawi said on Friday the "window" for a peaceful settlement of the stand off over Fallujah was closing fast.