Four Vietnamese were killed in Malaysia, Thursday, when their car plunged 30 meters to the bottom of a ravine.

The car broke through the guardrail near Gua Tempurung, a cave and tourist destination in the state of Perak.

Four Vietnamese women died; two more were listed among the four survivors.

Malaysian investigator Supt Aziz Salleh said "we believe that the vehicle was speeding", Vnexpress reported Friday, citing a Malaysia's Star report.

Aziz said the injured were in critical conditions.

The Toyota was carrying eight people including two native men when the accident happened on Malaysia's north-south expressway.

Police are investigating the relationship between the Malaysians and Vietnamese women.