STORY: Many ships could be seen around the Strait of Hormuz on Saturday, as sources said at least two commercial vessels reported being hit by gunfire while trying to cross the waterway.
Several others said they received radio messages from Iran's navy, saying they were not allowed to pass.
::File
It came as Iran said it was bringing back strict military controls on the vital trade route, saying the United States was still blockading Iranian ports.
In a statement reported by Iranian TV, a Revolutionary Guards spokesperson accused the U.S. of repeatedly breaching commitments and "acts of piracy and maritime theft under what it calls a blockade."
The state news channel also read out a message by Supreme Leader Mojtaba Khamenei, who said Iran's navy was ready to inflict "new bitter defeats" on its enemies.
::File
The tough messaging injected fresh uncertainty around the Iran conflict.
It raises the risk that oil and gas shipments through the Strait could remain disrupted, just as Washington weighs whether to extend a fragile ceasefire.
"They can't blackmail us..."
U.S. President Donald Trump said dialogue with Iran was ongoing.
"We'll have some information by the end of the day. We're talking to them. And, you know, we're taking a tough stand."
Iran's deputy foreign minister said his country remained committed to diplomacy.
But Saeed Khatibzadeh said no further talks with the U.S. would be scheduled until an understanding is agreed - that Iran will not give up what it sees as its rights under international law to uranium enrichment.
"We are member of Non-Proliferation Treaty, we are member of IAEA (International Atomic Energy Agency) and, and we are going to commit. We do have responsibilities and we do have rights. Iran is entitled to the rights and we are not going to abandon our rights."
::MarineTraffic
Earlier, maritime trackers had showed a convoy of eight tankers crossing the Strait.
It was the first major movement of ships since the U.S.-Israeli war on Iran began seven weeks ago.
::Beirut, Lebanon
Iran had announced its temporary reopening of the Strait, after a separate 10-day ceasefire agreement on Thursday between Israel and Lebanon, brokered by the U.S.
