Two men aged 29 and 18 from Levenshulme in Manchester, and a 21-year-old woman from Trafford are in custody.
A 29-year-old man from Oxford has also been arrested on being concerned in the commission, preparation or instigation of acts of terrorism, police said today.
The four are being questioned in Manchester.
Britain's senior-most counter-terrorism officer, Cressida Dick, has heralded a huge upsurge in arrests of would-be "jihadists" since the New Year, as Scotland Yard claims to pursue a more "sensitive" approach to terrorism.
"We're getting lots of support from families who are ringing up and saying they are worried about their brother, son, sister sometimes, friend or indeed from other sources of information and intelligence," she added.
An estimated 400 Britons have gone to Syria to fight, mainly with anti-Assad groups, some of which are linked to al- Qaeda. There have been more Syria-related arrests since the beginning of the year than there were in the whole of 2013, driven by parents who prefer to see their children arrested at home rather than killed on the battlefield.
"We are working effectively with those families, it's obviously a very complex issue particularly if it results in a loved one being arrested."
She urged more families to come forward.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
