At least five people were killed and one injured early Tuesday in a head-on collision on the Crimea Peninsula in southern Ukraine, the state traffic office said. The accident occurred on Simferopol-Kharkov highway at around 5 a.m. (0300 GMT), the office said in a statement. Four passengers from the two vehicles and one driver were killed, while the other driver was in serious condition. The cause of the accident was under investigation, but preliminary reports said speeding may be a cause.