Aden (AFP) - Gunmen killed two security officers in separate drive-by shootings in the southern Yemeni city of Aden, where jihadists are becoming increasingly active, security officials said on Sunday.

In the first incident, gunmen opened fire from a car at Major Meead Ali outside the building where he lives in the port city's Inmaa neighbourhood, one official said.

Gunmen shot dead Abdelwahed Ahmed of Aden's criminal investigation unit in a similar attack outside his home in Al-Mansura district, another security official said.

Meanwhile, the chief prosecutor of the neighbouring Lahj province, Saeed Abdullah, escaped an attempt to assassinate him in a similar way in Aden, a third security official told AFP.

All the attacks took place late on Saturday, the sources said.

Such assassinations by unidentified gunmen in cars or on motorbikes are common in Yemen, especially in the lawless south and are usually attributed to Al-Qaeda, although it rarely claims responsibility for them.

Aden has been rocked by unrest since Shiite Huthi rebels and their allies, who have seized the Yemeni capital before expanding further across the country, entered the city in mid-March.

Southern fighters allied with President Abedrabbo Mansour Hadi and supported by Saudi-led coalition forces managed in July to push the rebels out of the port city.

But Islamist militants, including Al-Qaeda and the Islamic State group, appeared to have gained ground in the southern city, where jihadists have become visibly present.

On October 6, government temporary headquarters came under attack in a series of bombings that lightly wounded several ministers and killed more than 15 people.

IS claimed the bombings which also hit military installations used by Saudi-led coalition troops.