AFP/East News

A period of national mourning has been declared by Poland's president following the tragic rail disaster that claimed the lives of 16 people on Saturday evening near the small town of Szczekociny, in the south of Poland.

The crash happened when two trains collided head-on as they were traveling on the Kraków-Warsaw mainline. The death toll stands at 16, with 58 injured. One of the dead is a US citizen.

On Sunday, President Bronisław Komorowski announced the start of a two-day period of national mourning.

"The scope of this disaster is sufficiently large to warrant national mourning," he said.

Prime Minister Donald Tusk has called it the "most tragic train catastrophe ... in many years."

One of the trains was traveling from the eastern city of Przemyśl to Warsaw, while the other was heading south from Warsaw to Kraków. It is still not clear why the southbound train switched to the wrong track minutes before the crash.

The accident is being investigated by public prosecutors and by a special accident investigation committee. The two trains were carrying 360 passengers, including travelers from Ukraine, Spain and France.

President Komorowski visited the crash site and a hospital where some of the wounded were admitted. Among the injured passengers, three are said to be in a very serious condition.

Prime Minister Tusk, as well as Interior Minister Jacek Cichocki and Minister of Transport Sławomir Nowak, also visited the scene of the disaster

Poland A.M.