An explosion went off near a car carrying a British diplomat in the Yemeni capital, Sana, on Wednesday, news reports said.
In London, the British Foreign Office said there had been an attack directed at a British Embassy vehicle but there were no casualties among diplomatic staff. Some reports said the car had been attacked with anti-tank grenades and there may have been casualties among bystanders.
There was no immediate claim of responsibility for the attack.
But the reports underscored concerns among Western counterterrorism experts that Yemen is emerging as a crucial testing ground for the Obama administration’s approach to countering the threat from Al Qaeda.
The attack was launched two days after Yemeni authorities tightened security around embassies in Sana following reports that Al Qaeda planned an attack, The Associated Press reported.
Last April, the British ambassador in Yemen was unhurt after a suicide bomber detonated his explosive belt as the diplomat’s armored convoy was passing.
In a separate incident, an unidentified French citizen died on Wednesday in a shooting incident at a compound for staff from an Austrian oil and gas company, OMV, near Sana, news reports said. Security personnel disarmed a gunman at the compound. It was not clear if the shooting was linked to terrorism.
In the past, United States officials have expressed concern that the Yemeni government was not taking the threat of terrorism seriously enough, though it has worked more closely in recent months with the American military on counterterrorism efforts, including several American airstrikes.
The United States Central Command has proposed supplying Yemen with $1.2 billion in military equipment and training over the next six years, a marked escalation on a largely hidden front in the campaign against terrorism.
The aid would include automatic weapons, coastal patrol boats, transport planes and helicopters, as well as tools and spare parts. Training could expand to allow American logistical advisers to accompany Yemeni troops in some noncombat roles.
Opponents, though, fear American weapons could be used against political enemies of President Ali Abdullah Saleh and provoke a backlash that could further destabilize the volatile, impoverished country.
The Yemen quandary has sharpened since Dec. 25 when a Nigerian man trained in Yemen allegedly attempted to bomb a Detroit-bound airliner. American officials say a central role in preparing the attack was played by Anwar al-Awlaki, the American-born radical cleric now hiding with Al Qaeda in the Arabian Peninsula, the network’s branch in Yemen.