Kuwait and Saudi Arabia have agreed to halt oil production from the joint Al-Khafji field for one month, starting from June 1, Kuwait’s Al Rai newspaper reported on Saturday.

There was no immediate comment from Kuwaiti officials.

Saudi Arabia and Kuwait have agreed with other members of the OPEC+ group of oil producers to cut output in a bid to reduce a glut in global supplies. Both Gulf states have also said they would make additional cuts beyond the agreed curbs.

Meanwhile, the FBI is probing several Mexican and European companies allegedly involved in trading Venezuelan oil as it gathers information fora U.S. Treasury Department inquiry into possible sanctions busting, according to four people familiar with the matter.

U.S. Secretary of State Mike Pompeo and special envoy for Venezuela Elliott Abrams told reporters late last month the State and Treasury departments were investigating whether several firms were violating sanctions imposed on Venezuela’s state oil company PDVSA since January 2019.

The sanctions are part of a campaign by Washington to strangle the revenues of President Nicolas Maduro, which has failed to break his grip on power. U.S. officials say privately that is a source of frustration for President Donald Trump, whose administration has tightened the implementation of sanctions in recent months.

Three of the people who provided information to the FBI -who asked for anonymity to discuss the matter – said the agency was investigating three Mexican companies: Libre Abordo, Schlager Business Group, and Grupo Jomadi Logistics & Cargo.

Reuters could find no record of Venezuelan oil purchases by those companies prior to sanctions.