Burma says it will not allow U.S. naval ships to deliver emergency aid to victims of Cyclone Nargis, which devastated the country's Irrawaddy delta earlier this month.

The official New Light of Myanmar newspaper says aid from the United States would come with "strings attached."

However, the official newspaper did express gratitude for supplies already airlifted into Burma by U.S. military aircraft.

United Nations Secretary-General Ban Ki-moon will arrive in Burma Thursday in an effort to boost relief efforts.

The U.N.'s top relief official, John Holmes, says he met with Burmese Prime Minister Thein Sein on Tuesday about the relief efforts.

The world body says it has received permission from Burma to deploy nine helicopters to deliver emergency aid.

A group of homeless Myanmar cyclone survivors take refuge at a monastery, being used as a temporary shelter, on the outskirts of Rangoon, Burma, 21 May 2008

Mr. Ban told reporters in New York Tuesday he hopes to meet with Burmese officials and press them to allow more international relief into the country.

Mr. Ban also said he wants to see for himself the situation on the ground, where the May 3 cyclone left 78,000 people dead and another 56,000 missing. Another 2.5 million survivors are vulnerable to famine and disease.

The Burmese government on Tuesday began three days of official mourning for the dead and missing.

Some information for this report was provided by AFP, AP and Reuters.