LONDON - British prosecutors charged a man on Tuesday with plotting to attack US military personnel based in Britain and planning to join Islamic State militants in Syria with his uncle.

The men, Junead Ahmed Khan, 24, and his uncle Shazid Ahmed Khan, 22, from Luton in central England, were arrested by officers last week and accused of preparing acts of terrorism.

"It is alleged that Junead Khan and Shazib Khan had been planning on travelling to Syria to join the proscribed organisation Islamic State in Levant (ISIL)," said Deborah Walsh, Deputy Head of Counter Terrorism at the Crown Prosecution Service.

"It is further alleged that Junead Khan was planning a terrorist attack on US military personnel in the UK and he has been charged with an additional terrorism offence to reflect this."

The men appeared at London's Westminster magistrates court later on Tuesday and were remanded in custody until their next appearance at the Old Bailey court on Aug. 10.

No further details were given of what the authorities believe was the target of the alleged attack.

However, events to celebrate US Independence Day over the weekend of July 3 and 4 at RAF Feltwell, used as a housing estate for US Air Force personnel which is about 60 miles (100 km) from Luton, were cancelled "due to the most current local threat assessments".

"While we were certainly looking forward to this year's celebration and hosting the US and UK communities at RAF Feltwell, we have to put public safety first and foremost," said Colonel David Eaglin, the vice commander of the US 48th Fighter Wing, at the time.