Iran's Revolutionary Guard said early Sunday that two oil tankers caught fire after striking naval mines in the Strait of Hormuz, the narrow waterway that carries much of the world's oil and has become the front line of the war between Iran and the United States.

The Guard's navy said in a statement on its official news outlet that one tanker hit a mine east of the strait and the other struck one while crossing it. Both ships had switched off their navigation and GPS systems and were burning after the blasts, the statement said. It did not name the vessels or say whether anyone aboard was hurt.

Tehran called the two ships violators that tried to use an unauthorized route. It warned that any vessel working with the American military and entering the restricted zone in defiance of Iranian rules would hit mines too.

A cargo ship disabled hours earlier

The mine claim came hours after U.S. Central Command said one of its aircraft fired precision munitions at the stern of the M/V Huda, a cargo ship flagged in St. Kitts and Nevis, in the Gulf of Oman on Saturday. The command said the ship had visited an Iranian port and was trying to leave the region after its civilian crew ignored repeated warnings and tried several times to break the U.S. naval blockade.

Commanders told the crew to clear the targeted part of the ship before the strike. Central Command released video of the attack. It said U.S. forces have turned back 147 merchant ships that complied with the blockade since July and have disabled five that refused.

A new task force on land

Also on Saturday, Adm. Brad Cooper, the head of Central Command, ordered the creation of Task Force Iron Gate. The team of about 20 military and civilian staff will be based in Tampa, Florida. It will work with other agencies to stop Iran from moving advanced weapons, dual-use technology, sanctioned goods and illicit cash across its land borders and the Caspian Sea.

Cooper said the blockade has already kept Iran from selling more than $25 billion worth of crude oil in recent months and that the new effort is meant to further squeeze the money Tehran uses to rebuild its military.

Blasts on Qeshm and a longer missile reach

Iranian state media reported two explosions on Qeshm Island in the strait on Saturday evening plus several blasts in the port city of Jask. The cause was not clear and the reports suggested they could be linked to Iranian military activity. On Friday the president said U.S. forces had carried out what he called minor strikes that knocked out an Iranian anti-aircraft system.

The Revolutionary Guard also said it had dropped its self-imposed 2,000-kilometer cap on the range of its ballistic missiles. Iran is not known to have longer-range missiles yet, but a wider reach would put the whole Arabian Peninsula, most of Egypt and parts of southeastern Europe in range.

The escalation comes as Iran weighs proposals from Qatar meant to narrow differences with Washington over its nuclear program, raising cautious hopes for indirect talks to end the war, now in its ninth month.