MSPs are calling for action over claims that Police Scotland has been "blocked" from investigating US rendition flights stopping at Scottish airports.
The cross-party group is concerned that officials from Westminster and Washington are refusing to provide the force with an unredacted US Senate report into alleged CIA torture.
They have written a letter to First Minister Nicola Sturgeon.
The Scottish government said the letter would be carefully considered.
It also said Justice Secretary Humza Yousaf was already seeking support from the UK government in getting the unedited report.
The US government was known to have used "rendition" tactics during the so-called "war on terror", which involved the detention of suspected terrorists and removal to another country where they were allegedly tortured for information.
It is alleged some Scottish airports were used as refuelling stops for these trips.
The current inquiry was requested by the Crown Office in mid-2013 after an academic study claimed that Aberdeen, Inverness and Wick airports were used in the rendition of suspected terrorists.
The study also identified the use of Prestwick, Glasgow and Edinburgh as fuelling stop-offs for these alleged rendition flights, often linking the US and the Middle East.
The letter, signed by members of the SNP, Scottish Labour, the Scottish Liberal Democrats and the Scottish Greens, urges Ms Sturgeon to call on Westminster to ensure the US Senate report is made available to Police Scotland.
The group also raises concerns that evidence could be destroyed by the current US administration, following a report from the New York Times in 2017 that President Donald Trump could order the unedited report to be locked away in Senate vaults or destroyed.
The letter said: "We are concerned that an ongoing Police Scotland investigation into this matter has been blocked from seeing vital evidence it needs to get to the truth.
"Specifically, officials in Washington and Westminster have failed to provide Scottish Police with an unredacted copy of the US Senate's report into torture undertaken by the US Central Intelligence Agency (CIA).
"This report contains detailed information about the CIA's rendition network. We urge you to call on the Westminster government to ensure this evidence is supplied."
Scottish Greens co-leader Patrick Harvie said: "I remember calling for this probe into this use of Scottish airports 15 years ago, and Police Scotland have been investigating since 2013.
"It is disgraceful that officers are still waiting for evidence, and deeply concerning that responsibility for transparency now rests with the Trump administration.
"Without a concerted effort now by the Scottish and UK governments, we might never get the truth."
He added: "As the UK government sidles up to Trump in the hope of a post-Brexit trade deal, it's vital the first minister pushes them on rendition."
Ch Supt Faroque Hussain, of Police Scotland, would not be drawn on the need for the force to be able to see the US Senate report.
However, he said: "Specialist officers from Police Scotland's Organised Crime & Counter Terrorism Unit have gathered and analysed all the information made available to them and have submitted a report which is being considered by the Crown Office."
A spokeswoman for the Scottish government said Justice Secretary Humza Yousaf would "give careful consideration" to the demands from the MSPs, and said he was already seeking support from the UK government in getting the unedited report.
Dan Dolan, deputy director of human rights campaign group Reprieve, said: "This is a major development in the investigation into how Scottish airports were used in CIA rendition flights.
"The Scottish government has made the right move today, and it must not let Westminster stonewall its efforts to get the evidence it needs. Nicola Sturgeon should tell Boris Johnson to stand up to Donald Trump on this issue".