Fears are growing for the safety of a number of Scots who are among the foreign nationals taken hostage by Islamist militants in Algeria.
Militants occupied a gas complex in eastern Algeria on Wednesday after killing a Briton and an Algerian.
They claimed to have 41 hostages, including French, British, US, Japanese and Norwegian nationals.
An Algerian military operation is under way at the facility near In Amenas, the UK Foreign Office has confirmed.
Unconfirmed reports from Algeria have suggested that two Scots have been freed by the army alongside a Kenyan and a French hostage.
The BBC understands at least one Scot who was being held is now safe.
Mark Grant, from Grangemouth, is believed to have been among the foreign nationals taken hostage at the gas plant.
He is now thought to be with the Algerian army. It is unknown if he was freed, rescued by Algerian forces, or managed to escape.
Media reports quoting militants said 34 hostages and 14 kidnappers had been killed in the operation.
Unconfirmed reports had also earlier said that a number of hostages - some 30 to 40 Algerians and 15 to 20 foreign nationals - escaped from the militants.
The Foreign Office would not confirm how many Scots were being held, but BBC Scotland understands it is fewer than five.
Speaking at First Minister's Questions, Alex Salmond told MSPs: "The chamber will know that a terrorist group has seized BP's Statoil facility in the Algerian Sahara.
"Citizens of a number of nationalities are involved, including UK citizens. I can confirm to the chamber a number of Scots are among the hostages.
"The UK government reports that one UK national has been killed in the attack."
Mr Salmond said that information was limited "in the interests of the safety and security of the hostages".
"The priority is their safety and, of course, to keep families informed," he said.
"The Scottish Police Service is fully engaged with the Metropolitan Police Service in the latter, and Scottish government ministers are in contact with Foreign and Commonwealth officers on the former.
"This is a hugely serious situation and I know that the whole chamber is united, both in condemnation of the attack and also in hoping for the early and safe release of the hostages."
The Scottish government said that ministers did not take part in the UK government's Cobra meetings on the situation, but were given information from the meetings.
The In Amenas gas field and its facilities are operated by a joint venture of the Algerian national oil company Sonatrach, BP and Statoil.
In its latest statement, BP said the incident was "continuing" and remained "unresolved and fragile"
BP's chief executive, Bob Dudley, said: "BP's overriding priority is to do all we can to ensure the safety of our staff and to support their families during this anguishing time.
"All our efforts are focussed on supporting the authorities to secure a peaceful resolution of the situation and the safe return of our colleagues, and all other workers being detained."