U.S. Secretary of Defense James Mattis pressed for a political settlement of the Yemen conflict between the Saudi-led coalition and Iran-backed Shiite Houthi rebels when he arrived in the Riyadh this week as part of a multi-nation tour of the Middle East and North Africa.

“In Yemen, our goal is to push this conflict into U.N.-brokered negotiations to make sure it is ended as soon as possible,” Mattis told reporters Tuesday after a series of meetings with Saudi Arabia’s King Salman, Crown Prince Mohammed bin Nayef, and Deputy Crown Prince Mohammed bin Salman.

“It has gone on for a long time… we see Iranian-supplied missiles being fired by the Houthis into Saudi Arabia, and this is something with the number of innocent people dying inside Yemen that has simply got to be brought to an end,” he stressed.

The Pentagon chief stopped short of urging America’s Sunni allies to drop a planned bombing offensive targeting the Yemeni port city of Al Hudaydah.

“Human rights officials have warned that bombing Al Hudaydah could lead to a humanitarian crisis in Yemen, and Mr. Mattis’s remarks were in line with those of many officials in the region that the Saudi coalition’s war against the Houthis, begun two years ago, cannot be won militarily,” reports the New York Times (NYT).

Retired Marine Gen. Mattis, who served as top U.S. commander in the Middle East, North Africa, and Central Asia, is also expected to visit Egypt, Israel, Djibouti, and Qatar.

While in the Saudi capital of Riyadh, he emphasized the need for cooperation among regional powers to tackle down mutual threats in an increasingly dangerous world.

In February, the Wall Street Journal (WSJ) reported that U.S. President Donald Trump’s administration was considering forming a military coalition with several Arab allies to combat their mutual enemy, the state sponsor of terrorism Iran.

The anti-Iran coalition would bring together Saudi Arabia, the United Arab Emirates (UAE), Israel, Egypt, and Jordan.

In Yemen, the Trump administration has intensified its offensive against al-Qaeda in the Arabian Peninsula (AQAP), considered by U.S. officials to be the jihadist group’s most potent branch.

The U.S. military has also gradually increased its assistance over the years for the Saudi-led Sunni coalition fighting the Houthis and their allies in Yemen, providing them with intelligence, logistics, and training for the alliance’s forces.

Sunni troops and their allies are reportedly taking on AQAP, which has capitalized on the Saudi-led coalition’s nearly single-minded focus to annihilate the Houthis.

Among the Saudi coalition members are the UAE, Qatar, Bahrain, Kuwait, Egypt, Jordan, Morocco, and Sudan.

“Mr. Mattis declined to provide specifics about what additional support the U.S. might provide Saudi Arabia in Yemen, instead suggesting that its primary focus is to push for a United Nations-brokered peace deal in the two-year-old conflict,” notes WSJ.

Last month, Thomas Joscelyn, a security expert at the Foundation for the Defense of Democracies (FDD), warned U.S. lawmakers that AQAP remains capable and intent on its efforts to build an Islamic state in Yemen.

“Al Qaeda is working to build Islamic emirates in several countries and regions, including Afghanistan, North and West Africa, Somalia, Syria, and Yemen,” he said. “Unlike its rivals in the Islamic State (or ISIS), al Qaeda has adopted a long-term approach for state-building.”

The FDD expert noted that the Saudi troops and their allies have primarily targeted the Iran-backed Houthis in Yemen, allowing AQAP to capture territory and recruit fighters.

“Some [Yemeni] tribal leaders are closely allied with AQAP, so much so that they have been integrated into the organization’s infrastructure. This has led to an awkward situation in which some of AQAP’s leaders are also partnered with Saudi Arabia, the United Arab Emirates, and [Yemeni President Abdrabbuh Mansur] Hadi’s government in the war against the Houthis,” declared Joscelyn.