Police have called for public help after two violent thefts in Melbourne’s north this morning.

In the first attack, four masked offenders smashed their way into a Thomastown service station with hammers and stole a large amount of cigarettes.

On that occasion the attendant was able to hide in a back room while the goods were stolen.

The second victim — at a Keon Park services station — wasn’t as lucky.

That offender was hit in the face and threatened with a knife and hammer while two masked thieves demanded cash.

Four more masked offenders entered the shop and stole cigarettes.

Both services stations are on Dalton Road, but police haven’t yet confirmed the thefts are connected.

Police say all offenders are of African appearance.

The Thomastown thieves fled in a silver SUV. The Keon Park thieves fled in a black sedan.

Police have urged anyone with information or who witnessed the events to contact Crime Stoppers on 1800 333 000 or submit a confidential report to Crime Stoppers at www.crimestoppersvic.com.au.