Anti-terror police are warning Britons not to travel to Syria even for humanitarian reasons following the arrest of four people on suspicion of terrorism offences.
Det Chief Supt Tony Mole, head of the North West Counter Terrorism Unit, said there was "widespread concern" that people going to fight or to help those caught up in conflict would be targeted for recruitment by extremist groups.
The warning followed the arrest of three men and one woman on suspicion of travelling to or supporting fighting in Syria.
Two men, aged 29 and 18 from Levenshulme in Manchester, and a 21-year-old woman from Trafford, were arrested alongside a 29-year-old man from Oxford. All four were being held in custody.
A number of properties were being searched. Police said that following the arrests there was no imminent danger to Manchester or the UK.
Mole said: "Like other major cities across the UK we have been aware for some time of people travelling to wartorn places for terrorism-related purposes. This is not a problem unique to Manchester or the northwest – it is an issue that affects different communities across the country and elsewhere.
"We look at every case on its own merits, but travelling to a warzone in order to be involved in conflict, or supporting those who do so, could make you potentially liable to prosecution for terrorism offences.
"Also, as well as posing a risk to themselves, there is the very real threat that they could pose a danger to our own communities when they return to the UK.
He added: "The National Prevent Programme sees officers working to assess how people are drawn into travelling to Syria to become involved in conflict and how to prevent others doing the same.
"There is naturally widespread concern about the situation in Syria and other conflict zones and the way that some will be driven to travel there to engage in humanitarian work or to take part in the fighting. We know that some have already lost their lives or been detained by the regime and badly treated.
"There are serious concerns that anyone travelling to Syria, whether for humanitarian reasons or because of a desire to support the Syrian opposition, may be targeted by extremist groups who want to recruit them. This could have serious repercussions for the safety of the individual concerned.
"By travelling there people will be causing distress and anxiety to their families and friends, not to mention the wider community.
GMP chief const Sir Peter Fahy previously said there was a "huge concern" about Britons arriving back in the UK after fighting in Syria.