Oil prices rose on Tuesday as tensions remained inflamed in the US after President Trump said the ceasefire agreement between the countries was “on life support,” while the Strait of Hormuz remained essentially closed to traffic, further pressuring global inventories.

Futures on Brent crude (BZ=F), the international benchmark, gained 3.6% to trade above just under $108 per barrel, while contracts on US benchmark WTI crude (CL=F) rose an equal 3.6% to trade north of $101.50.

Investors spent Tuesday morning looking for any signs of relief or renewed aggression in the Gulf region after President Trump told reporters on Monday that the Iranian response received by the White House was “garbage.”

In their response to a US proposal for a framework under which to reopen peace negotiations, Iran has demanded lifting the US naval blockade of the Strait of Hormuz, which has been choking off Iranian export revenues, as well as sanctions relief and some degree of control over traffic through the strait moving forward.

Tensions also flared over worries of a potential restart to a “hot war.”

Kuwait on Tuesday said Iran’s Revolutionary Guard Corps had launched a skirmish against an island within Kuwaiti territory, which the Kuwait Ministry of Foreign Affairs called a “flagrant violation of the sovereignty” of the country. The UAE, which has taken the brunt of Iranian missile and drone strikes, has reportedly been secretly striking Iran without disclosing the actions, the Wall Street Journal reported on Monday.

Read more: It's not just gas prices. How the Iran war is coming for your grocery bill.

The US said it struck Iran throughout the tail end of last week after Tehran fired on US warships transiting the Strait of Hormuz.

Traffic through the strait, a critical chokepoint for global energy flows, remained essentially halted Tuesday morning, adding to supply losses throughout the market. Saudi Aramco (2223.SR) CEO Amin Nasser said Monday that the world is set to lose 100 million barrels of oil supply each day the war continues.

As the strait has remained closed, global oil inventories have plunged. While a heavily oversupplied market heading into the war has helped keep prices contained as countries have been able to draw down ample inventories, that buffer is nearing exhaustion, according to JPMorgan.

Global stocks in OECD countries are now expected to reach operational stress levels by June, and operational minimum levels — the level below which pipelines, refineries, storage tanks, and other infrastructure can’t operate — by September, per JPMorgan.