Indonesia's president has toured the main town on Nias island as aid trickles in for victims of Monday's massive earthquake.

President Susilo Bambang Yudhoyono held talks with local officials and prayed with survivors on the island that was devastated by the 8.7 magnitude quake. At least two teenagers were pulled alive from the rubble Thursday.

Hundreds of powerful aftershocks are making the search for victims more difficult. Shortages of food, water and other supplies have been reported on Nias, where damage to the island's infrastructure is slowing aid delivery.

There are conflicting accounts of the numbers of dead from the quake. The United Nations says 624 people are confirmed dead so far, but several islands close to the quake's epicenter have yet to be contacted. Officials estimate the death toll could reach 1,000 or more.

There have been reports of looting by hungry survivors, and local aid workers say thousands of people need medical care. The United States said Wednesday it has dispatched two ships to the area to deliver supplies and medical care.

Australia, Japan and Singapore have also sent military aircraft filled with relief supplies, equipment and personnel.