US President Donald Trump signed an executive order Monday imposing tough new sanctions on Iran, targeting Iranian Supreme Leader Ali Khamenei, Foreign Minister Mohammad Jawad Zarif and leaders of the Iranian Revolutionary Guards.

Trump told reporters at the White House that the sanctions would freeze billions of dollars of Iranian funds and prevent Khamenei from accessing financial resources, adding that the supreme leader was responsible for what he called "Iran's hostile behavior."

"We are not seeking a conflict with Iran, but we will not allow it to have a nuclear weapon," Trump said, describing the nuclear deal signed by former US President Barack Obama with Iran as a "catastrophic agreement," an agreement that Trump announced since the withdrawal of his country. He stressed that the new sanctions come in response to the fall of Iran since the days of a US aircraft march.

"We are not asking for a conflict," Trump said as he signed the order in the Oval Office. "On the basis of Iran's response, sanctions could be ended tomorrow or could last for years to come, .

For its part, the US Treasury announced that the new sanctions include Iranian Foreign Minister Mohammad Jawad Zarif, and that Washington wants to reach a new agreement with Iran on its nuclear program, and will not allow it to possess nuclear weapons.

The ministry also said the sanctions were aimed at eight leaders of the Iranian Revolutionary Guards and would come into force later this week and that Washington had not consulted with its allies.

On the other hand, a senior State Department official said the United States is building an alliance with its partners to protect shipping lanes in the Gulf by providing control over all shipping traffic.

The source added that a coalition of countries will provide material and financial contributions to the early warning program, which aims to deter proactive will help the United States and its allies to follow the movement of cargo, and explained that the deterrent tools will include cameras and binoculars and ships.

US special envoy to Iran Brian Hawk said Washington was ready to lift sanctions on Iran if Tehran wanted to conclude an agreement, but "the agreement must come first."

"The United States wants a new agreement with Tehran, covering what it described as shortcomings in the current agreement," Hawk said in a telephone briefing from Muscat, capital of the Gulf region. He said Iran had rejected diplomatic action and chose to respond with violence and accused it of being behind the recent attacks on tankers in the Gulf waters.

The US envoy said Iran had benefited from the deal to raise its military spending and fund its militia in the region, but stressed that the sanctions imposed on Tehran have exacerbated political isolation and caused a decline in military spending.