Vienna (CNN Business) OPEC announced on Monday it will restrict the supply of oil for another nine months in a bid to support prices pressured by weakening economic growth and skyrocketing American production.

After five hours of wrangling in Vienna, the group unveiled an agreement to extend until the end of March 2020 the production cuts that were first implemented in 2017. Those cuts were due to expire.

OPEC said its decision was based in part on the fact that "economic bearishness is now increasingly prevalent" because of trade tensions, central bank policies and "geopolitical issues."

Additionally, OPEC agreed in principle to formalize a charter for cooperation with non-member producers such as Russia despite objections from Iran , which insisted the agreement must be ratified by national governments.

its most important outside ally on oil policy, met over the weekend to discuss extending the supply curbs that were first introduced after global oil prices crashed. Saudi Arabia , the biggest producer within OPEC, and Russia,its most important outside ally on oil policy, met over the weekend to discuss extending the supply curbs that were first introduced after global oil prices crashed.