At least 22 people were killed, including nine members of one family when a passenger van fell into deep ravine in southwest Pakistan, officials said on Wednesday.

The accident happened apparently due to excess speed at Quetta - Zhob highway in district Killa Saifullah 200 km (120 miles) from Quetta in Balochistan province, though the exact cause of the crash was not immediately known, officials said.

"Women and children are among those who died on the spot," Hafiz Qasim, district Commissioner of Killa Saifullah told Reuters.

One injured was sent to the Civil Hospital Quetta in serious condition, Dr Wasim Baig told Reuters.

Fatal road accidents are common in Pakistan, where traffic rules are rarely followed and roads in many rural areas are in poor condition.

Pakistan's President Arif Alvi has expressed sorrow over the accident and ordered authorities to make arrangements to deliver the bodies of passengers to their families.

In July last year, a jam-packed bus carrying mostly labourers traveling home for a major Muslim holiday rammed into a container truck on a busy highway in central Pakistan, killing at least 33 people.

(Writing by Syed Raza Hassan; Editing by Tomasz Janowski)