National Iranian Oil Company (NIOC) exploration manager said the contracts of three of the 17 oil blocks put out to tender will be finalized soon. Reportedly, 23 domestic and foreign companies have purchased the documents of 17 blocks, saying the majority of purchasers are international giants. Iran is attempting to lure international oil and gas companies to invest despite rising pressure from the U.S. over its nuclear energy program. Iran has this year been promoting an international exploration tender for 17 onshore and offshore blocks. The original deadline for receiving offers was June, but the NIOC announced early that month that it was extending the limit by a further month.