The National Accountability Bureau (NAB) has arrested five officials from Pakistan State Oil (PSO) and two private oil companies for their alleged involvement in a Rs63 billion oil scam, it said on Saturday.

The arrests were made on July 11 after a series of raids in Karachi, Islamabad and Gilgit, NAB officials informed media today.

NAB said it had arrested a former general manager (Supply) from PSO, Byco Pakistan Petroleum Ltd.'s (BPPL) former chief operating officer and BPPL's former president (Refineries) from Karachi.

PSO's former general manager (Retail and Consumer Business) and current chief executive officer of Jinn Petroleum from Islamabad were also picked up, while PSO's former senior general manager (Marketing) was arrested from Gilgit.

According to NAB, the PSO officials had sold crude oil worth Rs2.43 billion to BPPL between 2008-9, for which the state oil company received no payment.

In 2012, PSO allegedly entered an agreement with Byco Oil Pakistan Ltd (BOPL), even though the latter wasn't commissioned until 2013, NAB alleged.

Despite the company not being commissioned at the time of the agreement, the state oil company purchased substandard petroleum products from the firm, causing the national exchequer a loss of Rs60 billion.

In the same year, PSO also sold crude oil to BPPL at abnormally subsidised rates under another illegal contract with the private firm. The collective loss caused by the three agreements amounted to Rs63.69 billion.

NAB produced the suspects arrested from Karachi before an accountability court on July 12. PSO's former general manager (Supply) and BPPL's former president (Refineries) were sent on 13-day physical remand while BPPL's former chief operating officer was granted judicial remand on medical grounds.

The remaining two suspects will be produced before court on July 16.