Aid Trickles Into Indonesia Quake And Tsunami Zone

(CNN) Help trickled in Thursday, three days after a magnitude-7.7 earthquake struck off Indonesia, triggering a tsunami that has killed at least 311 people and left more than 400 missing.

An assessment team from the nonprofit group SurfAid International has begun surveying damaged villages on the islands of North Pagai and South Pagai, the group said Thursday.

Villages have either been destroyed or have suffered significant damage, SurfAid said.

The nonprofit is one of the few that have reached the remote disaster zone. The trip takes at least 10 hours in good conditions, according to aid agencies.

The hard-hit Mentawai Islands region is among Indonesia's myriad islands.

"The village of Sabeugungung has been completely wiped out, with 50 dead and 150 missing presumed dead. Sikakap hospital is overflowing with over 200 people seeking assistance," SurfAid said in a blog post.

Ten villagers in Bosua had been killed, another was missing, and 78 houses had been destroyed, the nonprofit said.