US national held in Saudi Arabia

The Saudi Arabian authorities have arrested a United States national in connection with two bomb attacks in the capital, Riyadh.

One Briton was killed when his car exploded in Riyadh in mid-November. A few days later, three Britons and an Irish woman were injured in another blast.

United Kingdom officials said they were told of the arrest by Saudi officials and the American embassy.

The man - identified as Michael Sedlak - was arrested about a week ago.

UK experts

Forensic experts from the UK had been helping the Saudi authorities with the investigation. They examined the car that exploded in Riyadh, injuring three Britons.

Police blocked off roads around the first blast

The experts concluded that the explosion was definitely caused by a bomb.

Some Saudi officials have suggested that the motive behind the bombings was personal rather than political, but the UK Foreign Office have voiced concern that someone with a grudge against the West may be targeting Britons.

The Foreign Office has advised UK nationals living in or travelling to Saudi Arabia to exercise "caution".

There are more than 25,000 Britons living in the country, many of them working in the defence industry.

The explosions come at a time of heightened tension in the Middle East because of the situation in Israel and the Palestinian territories.