Americans in the Gulf state of Kuwait were warned on Tuesday of possible attacks after the authorities busted an Al-Qaeda-linked cell allegedly plotting to attack US targets. "There are indications that terrorist groups seek to continue attacks against US interests in the Middle East, including Kuwait," said a State Department message circulated by the US embassy. "American citizens are reminded to maintain a high level of vigilance and to take appropriate steps to increase their security awareness." The message also advised Americans living or travelling in Kuwait to register with the embassy. The message said extremists might be conducting surveillance on Westerners, particularly at hotels, housing areas and rental car facilities.