At least five soldiers were killed in the Yemeni government stronghold of Aden in an attack on a security headquarters, local reports said.

Al Masirah, a TV network run by the Houthi rebels, said on Sunday that a car bomb targeting the criminal investigation department of the Khormaksar district was followed by clashes.

"The car bomb exploded in front of the security director's motorcade," the report said.

The apparent target was reported to have survived the attack.

It was not immediately clear who was responsible for the assault.

Images posted to social media showed plumes of smoke rising from the scene of the attack.

Al Jazeera could not independently verify the reports.

Sunday's violence comes a day after Houthi rebels claimed responsibility for a loud explosion in Riyadh, saying they fired a long-range ballistic missile that travelled more than 800km over the border with Saudi Arabia.

The war in Yemen, the Middle East's poorest country, started in 2014 after Houthi rebels seized control of the capital Sanaa and began pushing south towards the country's third-biggest city, Aden.

The Yemen government has been based in Aden and Saudi Arabia since 2014.

Concerned by the rise of the Houthi rebels, believed to be backed by regional rival Iran, Saudi Arabia and a coalition of Sunni Arab states launched an intervention in 2015 in the form of a massive air campaign aimed at reinstalling President Abd-Rabbu Mansour Hadi's government.

PHOTO CAPTION

Map of Yemen locating Aden

Al-Jazeera