Scotland is not safe from terrorism and members of the public should stay alert, the justice minister has said.

Her comments came after those by John Vines, head of the Association of Police Officers Scotland and chief constable of Tayside Police, who over the weekend claimed that al Qaeda operatives could be acting north of the border.

"Scotland is a terrorist target," he told the Sunday Herald.

"We have to be as vigilant as every other country.  Special Branch is monitoring people who are of interest to us but I could never say that we are on top of all the suspects."

"We don't know exactly how many terrorists may be in Scotland but we are watching people," he added.

"It is a frightening situation.  What we are seeing in intelligence terms is that we are very vulnerable and need to be vigilant to try to avoid being the victims of terrorist attacks."

Speaking on Monday, Cathy Jamieson said people in Scotland should be "alert but not alarmed".

"The horrific events in Madrid have confirmed that the threat of terror is a factor for every country in Europe," she said.

"Ruthless international terrorists are moble.  They do not respect borders.  Scotland is in no way a safe haven from these threats."

The justice minister will travel to Brussels on Tuesday to discuss the European approach to the war against terrorism.

"We are all rightly conscious of our unique legal systems and domestic structures - but in today's environment we cannot afford to be precious about them," she added.

"Scotland, like the rest of the UK remains on a high level of alert.  Security is kept under constant review to ensure we are as prepared as we can be.

"We are continuing to work very closely with our counterparts in the UK and EU in relation to this.  The public message remains the same - remain alert, but not alarmed."