Two men from Birmingham have been charged with planning and travelling to Syria to engage in acts of "terrorism".
Officers from the West Midlands Counter Terrorism Unit arrested Mohammed Nahin Ahmed and Yusuf Sarwar, both aged 21, at Heathrow Airport on Monday after returning to the UK on a flight from Istanbul.
The men are due to appear before Westminster Magistrates Court on Saturday.
The details of the charges, as authorised by the Crown Prosecution Service, are that Sarwar and Ahmed "on or before 15 May 2013, with the intention of committing acts of terrorism, engaged in conduct in preparation for giving effect to his intention namely planned and travelled to Syria, via Turkey, in order to engage in acts of terrorism."
It was not stated which groups the men were alleged to have trained and fought with in Syria. The British government has backed the opposition Free Syrian Army to topple the regime of Bashar al-Assad. However, London does not support groups such as the Islamic State of Iraq and the Levant or the Nusra Front, which have links to al-Qaeda.
In a separate case a 21 year-old man, also from Birmingham, was arrested on suspicion of attending a "terrorist" training camp in Syria.
No evidence needed
The man was initially detained under Schedule 7 of the Terrorism Act when he arrived on a flight from Istanbul to Gatwick on Friday. He was later arrested by officers from the West Midlands Counter Terrorism Unit.
The man was questioned at a police station in the West Midlands before being released on police bail pending further enquires.
Schedule 7 of the Terrorism Act says that UK police can stop, examine and search passengers at ports, airports and international rail terminals.
But there is no requirement for an officer to have a "reasonable suspicion" that someone is involved with terrorism before they are stopped.
British police have, during the past three years, arrested a number of people who have travelled to Syria over concerns that they are fighting with armed groups.
The foreign secretary, William Hague, said on Monday that "hundreds" of Britons were believed to have gone to fight in Syria and that security forces were doing their best to monitor the situation.
On Thursday, two women aged 26 and 27 were arrested on suspicion of terrorism offences, including one who was about to catch a flight to Istanbul.
Police would not comment whether these arrests were linked to Syria.