LONDON (REUTERS) - British prosecutors charged a man on Tuesday with plotting to attack US military personnel based in Britain and planning to join Islamic State in Iraq and Syria (ISIS) 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, using an alternative name of ISIS.

"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."

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

The men were due to appear at London's Westminster magistrates court later on Tuesday.