A car bombing killed a senior Yemeni military leader and three of his entourage in the southern port city of Aden on Wednesday, three security sources said.
The defense ministry confirmed that Brigadier General Thabet Gawas was killed in a "cowardly attack carried out by several terrorist elements" but provided no further details.
Gawas was returning from a personal visit when his car was hit by the blast in a suburb of the city, the security sources said. Aden's AIC Television showed footage of a car in flames.
There was no immediate claim of responsibility.
Gawas had long been an enemy of the Iran-backed Houthi militias, fighting them in their northern stronghold of Saada even before the 2014 coup against the legitimate government.
In 2004, he led the first military operation against the Houthi rebellion that ended with the killing of the founder of the militias, Hussein Badreddine al-Houthi. The operation earned him the name "Vanquisher of the Houthis" among several Yemenis.
He participated in operations that expelled the Houthis from the southern Lahj region in 2015. President Abdrabbuh Mansur Hadi named him commander of that region, a position he held until his assassination.
Security sources said terrorists had been monitoring his movement since his arrival in Aden earlier on Wednesday. He was on a personal visit and after departing, his vehicle was blown up. Two other cars were damaged in the attack.
Yemeni sources compared the bombing to the assassinations carried out by the Hezbollah party in Lebanon that is also backed by Iran and that has extended its expertise to the Houthis.
The defense ministry and the head of the Southern Transitional Council each issued statements mourning Gawas.
The Houthis did not hide their glee at Gawas' assassination with social media posts celebrating his death.
Supporters of the legitimate forces tweeted their sadness and condolences, describing Gawas as an extraordinary figure and hero, adding that they were not surprised with the Houthis' rejoicing of his death.