Israeli Prime Minister Benjamin Netanyahu shakes hands with U.S. Secretary of State Mike Pompeo during a meeting at the Prime Minister's office in Tel Aviv, Israel, April 29, 2018. (Thomas Coex/Pool via Reuters)

JERUSALEM, April 29 (Xinhua) -- The United States is "deeply concerned" about Iran's efforts to expand its forces in the Middle East, U.S. Secretary of State Mike Pompeo said after meeting Israel's Prime Minister Benjamin Netanyahu on Sunday.

"We remain deeply concerned about Iran's dangerous escalation of threats towards Israel and the region," Pompeo said during comments alongside Netanyahu.

The two met at the defense ministry in Tel Aviv amidst the newly-appointed secretary of state's three-day visit to the region.

The prime minister congratulated Pompeo upon taking office last week, saying Israel is "very proud of the fact that this is your first visit as secretary of state."

Pompeo called Netanyahu "an incredibly important partner" as a reply.

Commenting on the upcoming May 12 deadline when U.S. President Donald Trump is due to decide on the extension of the waiver on nuclear-related sanctions against Iran, Pompeo said that Trump will exit the agreement if the U.S. administration "can't fix it."

Pompeo also reiterated the U.S. commitment to relocating its embassy from Tel Aviv to Jerusalem on May 14. The controversial move has triggered a strong Palestinian condemnation and a new wave of violence between Israel and the Palestinians.

He also stressed that Trump said in December 2017 that the borders of the Israeli sovereignty in Jerusalem are subject to "negotiations between the sides," and the United States has remained committed to achieving "a long and lasting peace that offers a better future for both Israel and the Palestinians."

Pompeo arrived in Riyadh on Saturday, starting his first official trip outside the United States after he was sworn in last week. He is also scheduled to meet with officials of Israel and Jordan, which are key allies of the United States in the region.