Militants have fired a rocket-propelled grenade at a British embassy car in the Yemeni capital of Sanaa.
The UK Foreign Office said one member of staff was slightly injured and witnesses say at least three bystanders were hurt on Wednesday.
Following the attack on the embassy car, British Foreign Secretary William Hague told the BBC that all UK diplomats were remaining at home or in the embassy.
Mr Hague said the blast was "a reminder that we have some way to go" in efforts to make Yemen safer.
In a separate incident, a security guard is said to have opened fire in the compound of Austrian gas firm OMV near Sanaa, killing a French employee, Reuters reports.
The incidents come two days after Yemeni authorities tightened security around embassies in the capital following information of a planned attack by al Qaeda.
In April, a suicide bomber threw himself at the British ambassador's convoy in Sanaa as it neared the embassy compound, the BBC reports.
The attacker injured three passers-by and damaged a police car. Al Qaeda in the Arabian Peninsula later claimed responsibility.