At least 90 people are feared to have drowned after a migrant boat capsized off Libya, the UN Migration Agency has said.

Olivia Headon, from the International Organisation for Migration, said most of those on board were Pakistanis.

The bodies of two Libyans and eight Pakistanis are reported to have washed up on Libyan shores, she added.

Early indications suggest the vessel became unbalanced.

Security officials in the western Libyan town of Zurawa said two Libyans and one Pakistani had survived.

"We are told that two survivors swam to shore, and one person was rescued by a fishing boat," Ms Headon told reporters.

Ms Headon added that Pakistani nationals had been taking an increasingly large share of migrants trying to cross the Mediterranean via Libya to Europe.

Zurawa - near Libya's border with Tunisia - is often the site of migrant boat departures.

The numbers of people trying to reach Europe from Libya has dropped sharply since July.

Libyan authorities have blocked departures after pressure was applied by Italy and the European Union.

Over the last four years, more than 600,000 people are believed to have made the journey from Libya to Italy.