A US defence contractor working at the King Abdul-Aziz air base in Jubail was shot on 1 May, the day after the US embassy in Riyadh warned of intelligence suggesting an increased threat. 'The embassy -has received information that terrorist groups may be in the final phases of planning terrorist attacks on American interests in Saudi Arabia,' said the statement. The US worker sustained only minor injuries. The gunman, described as being dressed in a Saudi naval uniform, escaped. Hours after the incident, Washington renewed its advice against travelling to Saudi Arabia and urged its citizens to consider leaving the kingdom. 'Private US citizens currently in Saudi Arabia should evaluate their own security situations and should consider departing,' said the US State Department. There have been a series of gun attacks against Western defence workers in Saudi Arabia over recent months. The latest comes just days after Washington announced the withdrawal of its troops from the kingdom.