At least 17 people were killed and 12 injured in Angola on Tuesday when two trains crashed head-on in the country's southwest, according to the office of the region's governor.The accident happened in the early hours near Munhino in Namibe province when a train run by the state rail operator smashed into a stationary maintenance train that was being operated by Chinese engineers."The accident claimed at least 17 lives including the two drivers, one Angolan and one Chinese, as well as injuring 12," said the governor's office in a statement.An investigation into the incident which appeared to have been caused by human error has now been launched, it added."An on-duty railway employee was warned by the Chinese maintenance crew but could not prevent the departure of the train, loaded with granite, from Lubango station", said a local official who declined to be named."When he realised his mistake, it was too late to avoid a disaster."The incident is the second since the beginning of the year on the 260km line between Lubango and Mocamedes.A train derailed in February but no fatalities were reported.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.