Al-Qaeda has launched a number of attacks against Westerners and against Yemen's government, which declared war on the group's local arm after it claimed a failed attack on a US-bound airliner in December.

Yemen's President Ali Abdullah Saleh visited France this week to discuss the security situation in the Arab world's poorest state with President Nicolas Sarkozy after the French citizen was killed in a shootout outside the compound of oil and gas group OMV.

"Taking account of the deterioration in the security situation after the latest events in Yemen, we urge French expatriates to exercise greater vigilance and caution," a Foreign Ministry statement said.

"Spouses and children are asked to leave Yemeni territory. This is a precautionary measure taken in conjunction with the main French companies on the ground and after informing Yemeni authorities," the statement said.

France's embassy in Yemen will continue to function normally.

On Tuesday, Al-Qaeda's offshoot in Yemen warned it's setting up a "new army" to overthrow the country's president in response to his US-backed counterterrorism campaign.

Yemen's Al-Qaeda-allied militants and others have long sought to topple President Saleh.

Meanwhile, 10 years after a blast ripped through the USS Cole, killing 17 US sailors, US President Barack Obama said Tuesday that Al-Qaeda is pursuing a "murderous agenda" in Yemen.

Denouncing Al-Qaeda's "outrageous attack" that also injured 39 other sailors, Obama paid tribute to "the courage and sacrifice of those who lost their lives in this attack, and to their families."

Over the past decade, Yemen has morphed into a haven for violent extremists, becoming the headquarters of Al-Qaeda in the Arabian Peninsula and the hiding place for US-born radical cleric Anwar Al-Awlaqi, who was linked to high-profile terror plots in the US.

"Al-Qaeda continues to use Yemen, as well as other places around the world, as platforms from which to pursue its murderous agenda, and we continue to work closely with our Yemeni and other global partners to counter the Al-Qaeda threat," the president said.

"As we do, we will always remember those we lost on the USS Cole, and we will honor their legacy of selfless service by advancing the values that they stood for throughout their lives."

The bombing took place just 11 months before Al-Qaeda militants hijacked planes in the Sept. 11, 2001 attacks that killed nearly 3,000 people in the United States.