MANILA, Jan. 31 (Xinhua) -- At least four people were killed and about 30 others injured when a speeding tour bus hit the rear of an 18-wheeler cargo truck in the northern Philippines early Thursday, local police said.

Police said the accident happened around 5:20 a.m. local time on an expressway north of the capital Manila.

The bus, carrying Philippine government employees from Cavite province, south of Manila, was on the way to Baguio City, the mountain city in the northern Philippines when the accident happened, police said.

The dead included a male tourist guide, two male passengers and a female passenger, according to local news reports.

Video footage posted on a Facebook showed the mangled front of the bus.

Local authorities are looking into the accident.