Russia has agreed with Saudi Arabia to extend a deal with the Organization of Petroleum Exporting Countries (OPEC) on reducing oil output by six to nine months, Russian President Vladimir Putin said, as oil prices come under renewed pressure from rising U.S. supplies and a slowing global economy.

Putin, speaking after talks with Saudi Crown Prince Mohammed bin Salman on Saturday, told a news conference the deal - which is currently due to expire on Sunday - would be extended in its current form and with the same volumes.

The OPEC, Russia and other producers, an alliance known as OPEC+, meet on July 1-2 to discuss the deal that involves curbing oil output by 1.2 million barrels per day (bpd).

The U.S., the world's largest oil producer ahead of Russia and Saudi Arabia, is not participating in the pact.

"We will support the extension, both Russia and Saudi Arabia. As far as the length of the extension is concerned, we have yet to decide whether it will be six or nine months. Maybe it will be nine months," said Putin, who met the Saudi crown prince on the sidelines of the G20 Summit in Osaka, Japan.

A nine-month extension would mean the deal runs out in March 2020. Russia's consent means the OPEC+ group may have a smooth meeting if OPEC's third-largest producer Iran also endorses the arrangement.

Saudi Energy Minister Khalid al-Falih said the new deal would help reduce global oil stocks, balance the market and spur investments in future energy supplies.

"The agreement confirms that the Saudi-Russian partnership paved the way to guarantee the interest of producers and consumers and the continued growth of the global economy," Falih tweeted.