The head of the Syrian Olympic Committee has been refused a visa to travel to London for the Games, according to reports.
There had been suggestions for months that General Mowaffak Joumaa would be barred from entering the UK because of his connection to the Syrian military.
The BBC said the application has been refused because of his links to the regime of Syria's President Bashar Assad.
The Home Office said: "We are not commenting on individual cases."
The troubled Middle East state has seen a recent spike in violence by the forces of President Assad's regime.
The Home Office is responsible for carrying out background checks on behalf of the International Olympic Committee (IOC) and advises the committee on whether an applicant is suitable for accreditation.
The Foreign Office is also involved in exclusion decisions. Particular interest would be shown in visitors from countries where there are human rights abuses.
Officials are expected to keep a close eye on Syria.
Foreign Secretary William Hague has compared the recent massacres in Syria to those in Bosnia in the 1990s while Prime Minister David Cameron has condemned the killings as "brutal and sickening".
The Syrian charge d'affaires in London has already been expelled in the wake of mounting condemnation of the attacks.
The regime has been condemned by Britain for its crackdown on opponents.
It is thought that Syrian athletes may receive visas because those of Olympic standard are not required to serve in the armed forces, but there is a question mark against General Joumaa and other officials.
An IOC spokesman said: "At this stage we have not yet received any official approach on this issue and it would be premature to comment on any individual cases."