Supporters of an academic who has been detained accused of spying in Tajikistan are pressing the British government to help secure his release.
The call came as Tajik Foreign Minister Sirojidin Aslov met officials in London.
The researcher, Alexander Sodiqov, was detained on 16 June in Tajikistan's restive Gorno-Badakhshan region.
He was conducting an interview in a park in the regional capital Khorog when officers took him away.
Mr Sodiqov, a native of Tajikistan, was working on a research project on conflict management in Central Asia, run by Britain's Exeter University.
Khorog, a small town in Tajikistan's remote and mountainous Gorno-Badakhshan region, was chosen as one of the case studies because of serious fighting between the army and armed local opposition forces in July 2012.
Mr Sodiqov's work included interviewing officials and civil society leaders on their efforts to deal with the aftermath of the conflict.
But after his first meeting with local civil society activist Alim Sherzamonov, plain clothes officers detained the researcher.
The following day Tajik media reported that Mr Sodiqov was being investigated on suspicion of espionage for an unnamed foreign country.
Local television then showed him during questioning by the National Security Committee.
In the eight-minute-long video, Mr Sodiqov gives a detailed account of his education and employment history which included stints with the Organisation for Security and Co-operation in Europe, OSCE and Unicef, the United Nations children's rights organisation.
Mr Sodiqov appeared composed as he gave details of the research project, including the payment he would receive for his contract.
But supporters raised concerns over sections of the film which were heavily edited, saying they appeared designed to discredit third parties.
Mr Sodiqov's arrest has been met with numerous calls for information, fair treatment and for his release.
A statement by several academic societies representing 30,000 researchers warned of a wider threat to intellectual freedoms.
Rights groups Amnesty International and Reporters Without Borders have spoken out on Mr Sodiqov's behalf.
Meanwhile local media have reported that the researcher could face treason charges with a potential jail sentence of up to 20 years.
Exeter University's John Heathershaw who is leading the conflict management project Mr Sodiqov was working on told the BBC he was at a loss to explain why his colleague had run into difficulties in Tajikistan.
"I have been conducting research there for 11 years and I have always been freely able to interview people. So it is mysterious to me why this has happened now."
Professor Heathershaw says that the research project is funded by an UK academic organisation and that Mr Sodiqov was not being paid by the British government.
"I call upon the [Tajik] government to release Alexander Sodiqov on the basis that he is an academic researcher," he said.
He also expressed concern that two lawyers chosen by Mr Sodiqov's wife had not been allowed to see him in detention.
But some observers have wondered whether Mr Sodiqov was asking the wrong questions at the wrong time.
The mountainous region of Badakhshan - locally known as Pamir - saw renewed violence in May after police shot dead suspected drug traffickers in Khorog, sparking protests.
And the military operation two years ago in which dozens of soldiers and armed opposition were killed is still fresh in the memory.
Signs of unrest have in the past been met with a swift media and communications blackout.
The Tajik authorities have struggled to gain full control of Gorno-Badakhshan which broadly supported the Islamist-led opposition during a five-year civil war between 1992 and 1997.
The autonomous region on the border with Afghanistan is physically remote and culturally distinct with the area's Pamiri population following the Ismaili branch of Shia Islam and speaking a different language from other Tajiks.