The United States has closed its consulate in Dhahran, in eastern Saudi Arabia, after a lone gunman was arrested outside its gate.
A U.S. embassy spokesman said the gunman is being questioned by Saudi police. The man was seen outside the consulate in Dhahran around 6 a.m., brandishing a weapon. The spokesman said that no one was injured or threatened.
But the incident is fraying nerves in Saudi Arabia after last week's triple suicide bombing in the capital, Riyadh. Those attacks killed 34 people and are believed to have been carried out by the al-Qaida terrorist network. It was the first time that civilians had been targeted indiscriminately in the Saudi kingdom.
Saudi and U.S. investigators are cooperating in the probe into the Riyadh suicide bombings. U.S. officials said they now believe that al-Qaida has a bigger network of agents operating in Saudi Arabia than initially thought.
Security sources in Riyadh say there are probably three to five al-Qaida cells operating in the kingdom, each with several-dozen members. Saudi officials have promised to hunt down those responsible for the attacks.