A passenger train derailed in eastern Iran early Wednesday, killing over 20 passengers and injuring at least 86 more, state media reported.

The train was reportedly carrying around 350 passengers. 

"The passengers lost their balance and flew around like balls," one of the eyewitnesses told the ISNA news agency. "The windows of our compartment were shattered... We managed to escape through the broken window."

Ambulances and three helicopters with rescue teams have been deployed to the remote area where communication is poor, reports said.

Roads and Urban Development Minister Rostam Ghassemi said the ministry was responsible for the incident and offered an apology.

"According to our initial information, construction work was taking place on the rail route," Ghassemi said was quoted as saying by the Fars news agency.  

"An excavator left behind on the tracks caused the locomotive driver to brake sharply and this led to the derailment of the wagons."

The authorities have issued arrest warrants for six people in connection with the accident, but did not specify the reasons behind the move.

What we know about the derailment

The derailment took place some 50 kilometers (30 miles) from the desert city of Tabas, on a track that connects the holy city of Mashhad with the central city of Yazd.

Several of the train's 11 carriages derailed in the early morning darkness, according to media reports.

A railway official told state news agency IRNA that the train crashed into an excavator before going off the rails.

Aerial footage showed train cars on their sides and rescue workers running at the disaster site as they helped the injured. 

State TV also showed visuals from a hospital where the injured were receiving treatment.

Iran has railway lines spanning almost 14,000 kilometers (8,700 miles) throughout the country. 

Iran saw its worst train disaster in 2004, when a train loaded with gasoline, fertilizer, sulfur and cotton crashed near Neyshabur, killing nearly 320 people and injuring 460 others.

Five villages were also damaged in the incident.

The latest derailment also comes amid protests over last month's building collapse which killed over 40 people.

dj, dvv/fb (AP, dpa, Reuters)