A passenger train came off the rails in northeastern Iran on Saturday, killing at least seven people, state radio reported, adding that the death toll is expected to rise.

'The train was en route from the northeastern city of Mashhad to Tehran. So far seven passengers out of 50 aboard have been killed and 12 wounded,' local official Mohammad Reza Kazami told state radio.

State television put the death toll at eight and said four people were in a critical condition.

In 2004, a runaway train laden with fuel and fertilisers derailed in northeastern Khorasan province, killing about 300 people.-Reuters