Khobar: State oil giant Saudi Aramco has asked firms to extend the deadline for bids to build one of the units at the 400,000 barrels per day (bpd) Yanbu refinery, industry sources said on Thursday.

The Yanbu project accounts for just under a quarter of the country's planned expansion of around 1.7 million bpd of refining capacity on top of the current 2.1 million bpd.

The state-run firm had previously asked engineering firms to extend the validity by 60 days to July 26 for bids for contracts for the Yanbu project.

The deadline has been pushed back further for the coker unit, the sources said, but it remains unchanged for other units.

"Aramco asked to extend validity date of package 1 to August 9," an industry source said.

US firm ConocoPhillips pulled out of the Yanbu project in April.

Long before it left the project, Conoco, together with Aramco, had forced contractors to submit revised bids in January to take into account lower costs of raw materials after the global economic slowdown.

Daelim Industrial was one of the most aggressive bidders for several packages and is poised to win deals to build a gasoline unit and a hydrocracker, industry sources said.

Other front-runners were expected to sign deals by the end of the month.