At least 37 people, including 11 pilgrims, were killed and several others injured in two separate bus accidents in Pakistan on Sunday.

The first accident occurred when a bus carrying 70 people veered off the Makran Coastal Highway in Balochistan province. At least 11 people were killed and 35 others injured in the accident. The bus was bringing Shia pilgrims back from Iran to Punjab province.

The Makran Coastal Highway is a 653 km national highway that extends along Pakistan's Arabian Sea coast from Karachi in Sindh province to Gwadar in Balochistan province. Most of the passengers involved in the accident were from Lahore or Gujranwala, according to police sources.

Hours later, 26 people were killed and three others injured when a bus carrying 35 people fell into a ditch in Pakistan-occupied Kashmir, Qamar Nadeem of Edhi Foundation, which runs the largest private ambulance service, said.

According to the sources, the cause of the accident — which occurred in a mountainous area — is not yet known.

Deputy Commissioner Sadhanoti, Umar Farooq, said that the deceased included children, women, and men, all of whom were from the Sadhanoti district.

The police, administration and rescue teams were present at the site of the incident.

The law enforcers said that some of the people have been identified.

President Asif Ali Zardari expressed sorrow over the loss of lives in the accident, offering his condolences to the families of the deceased.

"In this hour of sorrow, my sympathies are with the families of the deceased," he said, stressing the need to speed up the relief activities.

Punjab Chief Minister Maryam Nawaz offered her condolences and expressed regret over the loss of lives.

The accidents come just days after a bus carrying Pakistani pilgrims met with an accident in Iran, leaving 35 dead and 15 injured.