09:05 AM EDT, 07/22/2025 (MT Newswires) -- Oil prices weakened for a third-straight session early on Tuesday as supply is climbing while traders wait to see if U.S. President Donald Trump will follow through on his threat to impose tariffs on the country's trading partners next month.

In its final day as the active contract, West Texas Intermediate crude oil for August delivery was last seen down US$0.72 to US$66.48 per barrel, while September Brent oil was down US$0.61 to US$68.60.

The drop comes as supply is on the rise even while demand is expected to stumble as global growth is seen slowing amid U.S. tariff threats. OPEC+ has boosted production with three monthly tranches of 411,000 barrels per day as it returns 2.2-million bpd of production cuts to market and will add a further 548,000 bpd on Aug.1.

The supply hike comes as the global economy is expected to slow, with Trump threatening to impose fresh tariffs on the country's trading partners on Aug.1, though the president has failed to follow through on most of his prior promised tariff hikes.

"Tariffs have been repeatedly threatened but not enforced. Investors have largely shrugged off the noise, with markets often rallying after key deadlines pass uneventfully," Charu Chana, chief investment strategist at Saxo Bank noted.