Stocks increased and oil prices dropped below $100 a barrel Wednesday, following the announcement a day earlier of a cease-fire in the United States' war on Iran that would reopen a critical passage for the world's oil supply.

President Trump announced the ceasefire less than two hours before his deadline for Iran to reopen the passage, the Strait of Hormuz, or suffer attacks on its civilian infrastructure, Reuters reported. 

Roughly 20% of the global oil supply passes through the strait. Tankers allied with the U.S. and Israel – which launched joint attacks against Iran on Feb. 28 – passing through the strait have since been targeted.

Iran said it would stop counterattacks and allow safe passage through the strait if attacks against it stop.

While still above pre-war levels, Brent oil futures were last down 13.7% at $94.29, and U.S. crude futures were down 16% at $94.93 a barrel.

European stocks rose 4%, ​after strong gains across Asian markets, and Wall Street futures signaled gains of 2.7%-3.5%.

Meanwhile, the U.S. dollar fell broadly, after having been the currency of choice ​during the war, with the index against other major currencies easing to 98.842.

U.S. Treasuries surged after the ceasefire announcement, and the yield on the benchmark U.S. ​10-year Treasury note dropped to 4.2438%, the lowest since mid-March, while the U.S. 2-year Treasury notes sank to ​3.7318%.