The assault in eastern Hadramawt province comes as a yearslong cease-fire between Saudi Arabia and Yemen's Houthi rebels largely has held despite the militants' ongoing attacks against shipping in the Red Sea corridor. While the Houthis did not claim the attack, at least one Houthi official praised it as being “the beginning and an indication of a harsh future awaiting the invaders.”

Meanwhile, U.S. warplanes carried out new strikes targeting Houthi positions that lasted into early Sunday morning, the American military said.

The strikes come after the militants likely shot down yet-another American reconnaissance drone over the country.

The attack on the Saudi troops took place Friday night in Seiyun, a city some 500 kilometers (310 miles) east of Sanaa.

As troops worked out at a Saudi-led base there, the soldier opened fire, killing an officer and a noncommissioned officer, the state-run Saudi Press Agency said, citing a military statement.

“The Joint Forces Command underscores that this ‘Lone Wolf’ cowardly attack does not represent the honorable members of the Yemeni Ministry of Defense,” the statement added. The dead and the other wounded Saudi solider have been brought back to the kingdom, it added.

Aidarous al-Zubaidi, the leader of Yemen's successionist Southern Transitional Council, identified the soldier who carried out the attack as belonging to the First Military Region, which is based out of Seiyun.

Police in the area published pictures of the soldier, saying there was a 30-million-Yemeni-rial reward for information leading to the soldier's arrest. That's worth around $15,000 on the black market.

Authorities offered no motive for the attack.