More than one million victims of the cyclone in Burma, also known as Myanmar, have now received international aid as relief groups battle to reach hundreds of thousands more still stranded in remote areas, the United Nations said Tuesday.

About 42 percent of the 2.4 million people affected by the storm that hit the Southeast Asian country three weeks ago have received outside help, a spokeswoman for the U.N.'s emergency coordination body said.

The figure has increased steeply since the military-led government announced last week it would let in more foreign aid specialists.

Relief groups are hoping to capitalize on the junta's new openness to reach the 1.4 million people that are living in outlying areas who have so far received no international aid, said Elisabeth Byrs, a spokeswoman for the U.N. Office for the Coordination of Humanitarian Affairs.

The government too has been distributing assistance to cyclone victims but the U.N. does not know how many people were reached this way, she said.

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"Most of the assistance has been delivered to the people living in Rangoon division, because it was easier to reach them than in the delta," Byrs told reporters in Geneva.

"In the Irrawaddy River delta we have a logistical nightmare because of the hundreds of rivers and small islands," she said. "Some places are only reachable by inflatable boats. It's a problem, a major problem."

Cyclone Nargis killed at least 78,000 people and left another 56,000 missing when it hit Burma on May 2-3. Aid groups are still considering the situation an emergency even though the government says it is time to move on to reconstruction.

The World Health Organization said it has received reports of cholera cases being treated at hospitals in the Rangoon area, but so far there has been no confirmation from the government.

"WHO ... has requested clarification from the Ministry of Health," said Fadela Chaib, a spokeswoman for the U.N. health agency.

Malaria, dengue fever, cholera and other water-borne diseases are endemic to the area, but there have been fears that the continued flooding in the region and lack of proper infrastructure could worsen the regular occurrence of these illnesses.