TEHRAN - U.S. President Donald Trump fired his Secretary of State Rex Tillerson on Tuesday with a Tweet, as Tillerson was returning to Washington from a week-long trip in Africa assuming that he was still holding the position.

Trump appointed Mike Pompeo, who previously was the head of the Central Intelligence Agency (CIA), as the Secretary of State.

President Trump said his disagreement with Tillerson over some issues, including the Iran nuclear deal of July 14, 2015, known as the Joint Comprehensive Plan of action (JCPOA), led him to the decision.

“I used to work with Mike Pompeo,” said Trump. “He is always in a state of high energy and intelligence”.

But who really is Pompeo? What common views does he have with Trump?  And what policy will he adopt on Iran?

Pompeo, known as a fierce critic of the Iran nuclear accord, has been appointed when Washington is only two months away from the next deadline for maintaining the JCPOA intact.

A U.S. refusal to confirm commitment to the deal would mean that the White House would continue sanctions. The U.S. government says that without “reforms” in the JCPOA, it won’t uphold the deal.

Pompeo, 54, as the director of the CIA, constantly informed Donald Trump of the most recent security issues. He is one of the most radical figures in U.S. foreign policy and has close ties with Trump. He is one of the toughest opponents of Iran's nuclear deal and has repeatedly called for its abolition.

He has also recently claimed that Tehran is taking ruthless in desiring to become the top power in the region.

Supporting Trump, the former CIA director had also repeatedly stated that Washington's behavior with Pyongyang must be harsh enough to keep North Korea from continuing its nuclear and missile activities.

Pompeo considers Russia's involvement in the 2016 U.S. presidential election insignificant, saying that Russia has been interfering in various U.S. elections for decades. In February, he defended his talks with heads of Russian intelligence agencies at the CIA's central building.

The new Secretary of State supports the restoration of massive surveillance program including bulk collection of metadata and its combination with more information on citizens such as financial and lifestyle details that are accessible in a huge, searchable database.

Prior to his appointment as the director of the CIA, Pompeo was representing Kansas in the U.S. House of Representatives.

The new U.S. Secretary of State is a retired military officer who graduated from the U.S. Military Academy at West Point, iNew York. He also holds a degree from Harvard Law School.