College chiefs have warned of the "serious and very real threat" posed by men in a blacked-out mini-bus who are said to have tried to kidnap students.

It comes as girls and young women are warned to be wary after reports of the men trying to lure youngsters into a vehicle on at least four occasions.

Police are aware of four reports in recent days of girls aged 12 to 18 being approached by a vehicle in Dartford.

Now a letter from the Reynolds Dance Academy in Kent Road has warned parents and students to be extra vigilant.

It says: "Two of our 1st year students were confronted with a potential abduction last Monday.

"There are a group of foreign-sounding men driving around in a grey mini bus with blacked-out windows.

"Given this serious and very real threat we would ask that you do not allow any of your children - no matter what age - to travel to or from the studio on their own or even in small groups without an adult."

The college insisted all students were brought to the door and collected by a parent or guardian.

Police have now stepped up patrols... but are warning girls not to panic.

In a separate incident, one woman, who didn't want to be named, said she was leaving work last night in Kent Road, in the centre of town, when she was approached by a group of students.

She said: "They told me 'don't walk home on your own, a man has been trying to get girls into his van'.

"I was very worried, I called my dad to pick me up."

"Given this serious and very real threat we would ask that you do not allow any of your children - no matter what age - to travel to or from the studio on their own" - the Reynolds Dance Academy

All of the girls who have been approached so far have done right thing by not getting in the vehicle and then reporting the incident to police.

None of them has been touched or harmed.

Officers are making inquiries and will be stepping up patrols around the district.

A police spokesman said: "While we would ask people to remain vigilant, we would urge people not to panic as these incidents are very rare.

"There are basic safety steps we would encourage all residents to follow."

Safety Steps:

• If you are walking at nightavoid travelling alone and taking shortcuts through isolated areas,stick to well lit and busy areas.
• Plan your route before you go and let others know where you are going and when you will be back.
• Be alert to what is going on around you. When out walking, don't listen to MP3 players through headphones or speak for too long on the phone.

Anything suspicious should be reported to police on 999 if it is an emergency or life is in danger, or 101 if it is not an emergency.