SZCZEKOCINY, Poland (AFP) -- Rescue workers Sunday combed the wreckage of a head-on train crash in southern Poland as the death toll climbed to 16, with scores wounded in the country's worst rail disaster since 1990.

"People from across Poland and citizens from other countries suffered in the catastrophe," President Bronislaw Komorowski said upon his arrival at the scene near the town of Szczekociny, adding that he would call a national mourning period "as soon as the rescue operation is over."

Rescue workers had toiled overnight to pull survivors from the wreckage of the crash, which occurred Saturday evening. The cause has yet to be determined.

"I can confirm 16 fatalities. We have just pulled a victim from the wreckage, but we cannot rule out other casualties until all the wreckage is searched," Pawel Fratczak, an emergency services spokesman told AFP.

"I can say the stage of the operation to evacuate the injured is now over," he added.

"We have sent in six sniffer dogs specially trained to locate survivors and bodies. They did not indicate anything."

Fifty-six people were hospitalised Sunday morning, including one person who was in a serious condition, emergency officials said.

Ukrainian nationals were reported to be among the injured in the disaster, while French and Spanish citizens were also on the trains but apparently not injured.

Emergency services were preparing Sunday to remove the mangled engines and carriages from the track.

"This is the worst catastrophe in years," Poland's Prime Minister Donald Tusk told reporters at the scene late Saturday.

A total of 350 passengers were on board the two trains which collided head-on at around 9:00 pm (2000 GMT) Saturday as they were travelling on the same track, according to Poland's PKP railways.

One train was en route to the southern city of Krakow from the capital Warsaw, while the other was bound for the capital from the southeastern city of Przemysl.

Investigators gave no early indication as to what caused the crash, which happened on a stretch of the line that had recently been modernised, according to Transport Minister Slawomir Nowak.

Images of the wreckage showed tonnes of mangled metal. Three carriages and the two locomotives from both trains had jumped the tracks and were piled high on top of each other.

Saturday's accident was the worst rail accident in Poland since 1990, when 16 people were killed in a collision between two trains in the Warsaw suburb of Ursus.

Poland's worst train accident was in 1980 when 67 people died and 62 were injured in a collision between a passenger and a freight train in Otoczyn, near Torun, northern Poland.