POCHEON, South Korea-- More than 20 cars were involved in a pile-up on an expressway in the northern city of Pocheon Sunday, and fire authorities are working to determine if there were casualties, officials said.

The multi-vehicle crash occurred at around 9:15 p.m. on the Guri-Pocheon Expressway in Pocheon, 46 kilometers northeast of Seoul, and the authorities issued an emergency response mode to handle the situation, according to the officials.

It is not yet known if there were any casualties.

Source: Yonhap News Agency