Scotland's health secretary is refusing to say why the army has been called in to help NHS Ayrshire & Arran.
Ayrshire Live told last week how a request had been lodged with the military to offer support for under-pressure services.
But both NHS Ayrshire & Arran bosses and Mr Yousaf are staying tight-lipped on what roles the soldiers will be required to perform.
Raising the issue in the Scottish Parliament, South Scotland Conservative MSP Sharon Dowey said: "Unlike other health boards, NHS Ayrshire & Arran is the only one to request military help with general services on top of their additional duties.
"NHS Ayrshire & Arran refused to comment as to why that help is needed and what the military personnel will be doing.
"Can the cabinet secretary shed any light on that situation and assure me that NHS Ayrshire & Arran is the only health board where military personnel are performing general duties, rather than those that were agreed previously?"
Responding, Mr Yousaf said: "The request from NHS Ayrshire & Arran is now with military joint command.
"At this stage, it would be inappropriate for me to give further details of the number of personnel involved and what duties they will be performing.
"That is partly because it is not my decision; it is a decision for the military — the armed forces and services — to determine once they have received the request.
"Once we get confirmation from the armed forces about what additional capacity they are able to provide, I promise Ms Dowey that I will ensure that the information is made public and provided to her."
However, Ms Dowey has criticised the ongoing lack of clarity around the military's potential involvement.
She said: "It’s disappointing that the cabinet secretary for health won’t let us know what’s going on in our own health board, particularly given it’s the military that are involved.
"Humza Yousaf says It would be inappropriate to say how many troops will be helping out as that’s a military decision.
"That’s fine, but he could certainly have let parliament know what help NHS Ayrshire & Arran have requested, that’s not a military decision.
"If NHS Ayrshire & Arran are struggling that much, people have a right to know, both in the Scottish Parliament and in Ayrshire."
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