The campaign was launched after a rise in the number of Britons caught travelling or returning from war-torn Syria, from 25 arrests last year to 40 in the first three months of 2014 was reported.
UK authorities have long expressed fears about aspiring jihadis travelling to Syria for terrorist training, and it is thought that hundreds of Britons have already been there.
"We want to increase their confidence in the police and partners to encourage them to come forward so that we can intervene and help. This is not about criminalising people. It is about preventing tragedies," she said.
Events in London, Birmingham and Manchester saw police reach out to women to help prevent more deaths.
The security chiefs think hundreds of people have gone from the UK to fight in Syria, some of whom have returned.
"There is no evidence that families know. Young people are just leaving without telling families and their families are the last to know, said Indian-origin Labour MP Keith Vaz, chair of the House of Commons home affairs committee whose report into counter-terrorism will be released by next month.
"The evidence we received is that the police don't know how to stop this. Part of the concern in British Muslim communities stems from a mistrust of the UK authorities," he said. "Part of the concern in British Muslim communities stems from a mistrust of the UK authorities."
The UK government has also urged Muslim communities to stop sending charity convoys to the region, asking them to work with major aid organisations with experience of war zones.
The country's Charity Commission is investigating at least two organisations amid fears that aid convoys have been used to funnel fighters and resources to jihadist rebels.
Only last week, a father from Brighton, Abubaker Deghayes, said that three of his sons had gone to fight in Syria, one of whom was killed in a battle.
