[Source: Reuters]

Iran seized two ships in the Strait of Hormuz on Wednesday, tightening its grip on the strategic waterway a day after U.S. President Donald Trump announced he was indefinitely calling ​off attacks, with no sign of peace talks restarting.

The status of a two-week-old ceasefire, due to expire earlier this week, remained unclear.

In a sharp about-face hours after threatening renewed violence, Trump made what appeared to be ‌a unilateral announcement on Tuesday that the U.S. would extend a ceasefire until it had discussed an Iranian proposal in peace talks to end the two-month-old war.

But Iranian officials did not say they had agreed to any extension of the truce, and criticized Trump’s decision to maintain the U.S. Navy blockade of Iran’s trade by sea, itself considered by Iran an act of war.

Iran’s parliament speaker and lead negotiator Mohammad Baqer Qalibaf said a full ceasefire only made sense if the blockade was lifted. Reopening the Strait of Hormuz, the slender chokepoint that carried a fifth of the world’s oil trade before the war, was impossible with ​such a “flagrant breach of the ceasefire,” Qalibaf said on social media.

“You did not achieve your goals through military aggression and you will not achieve them by bullying either,” he wrote in his first response to Trump’s announcement. “The only way is recognizing ​the Iranian people’s rights.”

Trump again backed away at the last moment from his repeated threats to bomb Iran’s power plants and other civilian infrastructure, which the United Nations and others warn would violate international ⁠humanitarian law.

But little progress has been made in ending the war that started with joint U.S.-Israeli attacks on Iran on February 28.

That leaves the two sides in a holding pattern with the crucial Strait of Hormuz still effectively shut, straining economies across the world.

Thousands of ​people have been killed across the Middle East, mostly in Iran and Lebanon, where the Iran-allied Hezbollah militant group joined the fighting against Israel.

The Islamic Revolutionary Guards Corps seized two vessels for what it called maritime violations and escorted them to Iranian shores, according to statements by ​the shipping companies and Iran’s semi-official Tasnim news agency.

It was the first time Iran has seized ships since the war began at the end of February.

The Revolutionary Guards also warned that any disruption to order and safety in the strait would be considered a “red line”, Tasnim said.

Brent, the international crude oil benchmark, closed above $100 a barrel for the first time in two weeks.

The ongoing blockade of the strait is driving up costs for businesses while major economies run down reserves and restrict consumption with millions of oil barrels cut off from key markets.