A strike group led by the USS Nimitz and including two guided-missile cruisers and a guided-missile destroyer sailed into the Gulf to operate and train with US partners and support the coalition fighting the Islamic State group, the US 5th Fleet said in a statement.

"The Nimitz Strike Group has been operating in the 5th Fleet area of operations since July, and is at the peak of readiness," said strike group commander Rear Admiral Jim Kirk.

The move came just days after US Secretary of State Mike Pompeo vowed to enforce an arms embargo and other international sanctions against Iran which the US says will resume on Saturday.

On Tuesday Pompeo vowed that Washington would prevent Iran from purchasing Chinese and Russian military equipment, even as European allies disagreed with Washington's stance.

"We are going to act in a way -- and we have acted in a way -- that will prevent Iran from being able to purchase Chinese tanks and Russian air defense systems and resell weapons to Hezbollah,"Pompeo said.

And on Wednesday he said the United States will enforce resumed United Nations sanctions on Iran starting next week, despite nearly the entire UN Security Council saying Washington does not have the grounds to do so.

"We'll do all the things we need to do to make sure that those sanctions are enforced," Pompeo said.

The United States regularly sends aircraft carrier groups into the Gulf for exercises and to support US and anti-IS coalition operations in Iraq and Syria.

But the Trump administration has sought to step up pressure on Tehran.

According to the International Atomic Energy Agency (IAEA), Iran has stepped up its nuclear development activities since the United States unilaterally withdrew from the 2018 nuclear accord.

Washington says that despite its withdrawal, it has the right to force the UN to reimpose sanctions on Iran for violating the agreement.