Oil prices gave up their gains on Monday after surging to their highest levels since late 2014, falling from above $70 a barrel after President Donald Trump said he'd announce his decision on the Iran nuclear deal on Tuesday.

The president said he will make an announcement on Tuesday at 2 p.m. ET.

Crude futures were earlier boosted by the latest troubles for Venezuelan oil company PDVSA and the looming decision on whether the United States will re-impose sanctions on Iran.

U.S. West Texas Intermediate crude futures ended Monday's session up $1.01, or 1.5 percent, to $70.77 per barrel, marking the first time since November 2014 that WTI had climbed above $70 per barrel. The contract was last up 5 cents at $69.77.

Brent crude oil futures were up 46 cents at $75.33 a barrel, having ended Monday's session up $1.30, or 1.7 percent, at $76.17 per barrel. The international benchmark also touched their highest level since November 2014.