The price of oil sank on Monday after US President Donald Trump urged the OPEC crude producers' cartel to help cut "high" prices and aid the "fragile" world economy.

By 1300 GMT, Brent North Sea crude for delivery in April had sunk $1.58 to $65.54 per barrel compared with Friday's closing level.

The US benchmark West Texas Intermediate for April dropped $1.29 to $55.97.

"Oil prices getting too high. OPEC, please relax and take it easy," Trump tweeted.

"World cannot take a price hike -- fragile!"

Oil prices had traded relatively flat for the morning session but fell sharply following the remarks.

The comments echo Trump's frequent call for the Organization of the Petroleum Exporting Countries (OPEC) to keep production high to limit rising oil prices that hurt economic growth.

Meanwhile, legislation targeting OPEC is advancing in the US Congress, potentially raising new financial and geopolitical challenges for the oil market.

Earlier this month, a House committee approved the "No Oil Producing and Exporting Cartels Act of 2019," or NOPEC, and a version of the bill also has been proposed in the Senate.

The bill would seek to prevent OPEC and allies from adjusting their production levels to affect oil prices.

Under the bill, sovereign immunity would no longer protect OPEC members from Justice Department antitrust enforcement.

OPEC and its unofficial leader, Saudi Arabia, at the end of 2016 reached an agreement with Russia to limit output in order to lift crude prices.

While the legislation enjoys bipartisan support, there is still no timetable for the proposal to be considered by the full Congress.