The row erupted after the senior Labour MP claimed that Swinney had not accepted an invitation for a briefing on the Marinera, a Russian-flagged vessel previously known as Bella-1, which was seized by the US on January 7.
Wick John O'Groats airport was reportedly used by US special operations planes, and the seized ship was spotted in the Moray Firth – escorted by the US military – on January 13.
READ MORE: Read in full: All the letters at the centre of the row between John Swinney and Douglas Alexander
On January 14, Swinney said he had been "deeply concerned" to hear that the ship was in Scottish waters, and that he had only learned of it through media reports.
During a visit to arms firm Leonardo’s Edinburgh factory on Thursday, Alexander said he had offered Swinney a briefing on the operations last week.
“The Scotland Act is very clear that defence and foreign affairs are reserved matters,” the Scottish Secretary said. “As a committed devolutionist, Scotland has two governments with respective and discrete responsibilities.
“I personally offered a briefing to John Swinney, the First Minister, in relation to the use of Wick airport – that hasn’t been accepted. But these issues are far, far too important to be subject to party politics.”
However, Swinney told reporters at Holyrood that he had written to the Prime Minister and received a “reply from Douglas Alexander which basically told me that this whole issue was none of my business”.
“If that’s what Mr Alexander is suggesting is an invitation to dialogue, I suggest he goes in and redrafts his letters before he sends them to me,” Swinney added.
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“I wrote back to the Prime Minister after my letter from Douglas Alexander because I was so dissatisfied with the juvenile content of Mr Alexander’s letter.
“I have now had a reply from the Prime Minister which offers me the dialogue and security information that I believe is necessary for the First Minister of Scotland to have, and I will pursue that.”
The SNP leader said he was looking for the UK Government to engage in “dialogue with the law officers of Scotland who, of course, have legal responsibilities now that the tanker is in Scottish waters”.
The Russian-linked Marinera tanker pictured in the Moray Firth (Image: Peter Jolly)
Swinney said he was “committed” to contributing to the national security of Scotland and the wider UK, but added: “I could do with a bit more assistance in the UK Government in the process, because the UK Government is incredibly difficult to engage on significant issues of national security, as in recent days, such as on the MV Marinera tanker, where the flow of communication between the Scottish and UK Governments has been absolutely appalling.”
The First Minister previously said he would have expected the Scottish Government to be “fully sighted” on security issues affecting Scotland’s waters.
Alexander has been Scottish Secretary since September last year , after Keir Starmer unexpectedly fired Ian Murray from the role.