The death toll from an earthquake that struck the northern tip of Indonesia's Sumatra island last week now stands at 39, with more than 2,500 injured and some 52,000 displaced, according to the United Nations’ latest report.

The 52,113 displaced people are about 28 percent of the population of the affected districts, the U.N. said, adding that six people are still missing and 16,560 houses and other buildings have been damaged, citing government figures.

Main roads that were damaged by the earthquake or blocked by landslides,  hampering relief efforts, have now been cleared, it said.

The Indonesian government has announced plans to end the emergency phase of the operation on July 17, after which relief efforts will end except, if necessary, in the worst-affected areas, the United Nations said.

On Tuesday, Subhan Sahara, head of the Central Aceh Disaster Mitigation Agency (BPBD), told the Jakarta Globe that many of the survivors had contracted diseases.

“The BPBD said that 2,150 refugees have been afflicted with health problems including fever, diarrhoea and upper respiratory tract infection,” the Globe reported.

The 6.2 magnitude earthquake was shallow – only 10 kms deep – and struck 188 km southeast of Banda Aceh, the capital of Aceh province, on July 2, the U.S. Geological Survey said.

The Indonesian archipelago is on the Pacific's "Ring of Fire" and is regularly struck by earthquakes.

In 2004 a magnitude 9.1 quake struck Aceh, triggering a huge tsunami whose waves killed more than 230,000 people in 13 countries around the Indian Ocean.