KIGALI, Rwanda — The number of Burundians fleeing political violence is expected to reach 500,000 this year, and the United Nations is seeking more land for refugee camps in neighboring countries, the U.N. refugee agency reported Tuesday.

Hundreds have died in the East African nation since April 2015, following President Pierre Nkurunziza's decision to seek a disputed third term.

Burundi has seen violent street protests, forced disappearances and assassinations, forcing many to seek refuge in neighboring countries. Some opponents have vowed to remove Nkurunziza by force.

UNHCR said more land needs to be allocated for existing refugee camps or for building new ones. Without it, "these countries will struggle to provide sufficient shelter and lifesaving services in the camp sites," the agency said.

The number of Burundian refugees already exceeds 380,000. Most are sheltering in Tanzania.

A group of United Nations human rights experts said Monday that civic groups and rights defenders in Burundi face growing repression amid sporadic violence.

A number of groups have been banned, and a bill passed by the national assembly in December compels local NGOs to obtain authorization from the interior minister for any activity and to transfer funds of foreign origin through the central bank.

Burundi's government has resisted international efforts to deploy peacekeepers in the country to help calm tensions.