The Organisation for Security and Cooperation in Europe (OSCE) has rejected accusations by Turkmenistan of "illegal activities" in the Central Asian state.
Turkmenistan said earlier this month it had uncovered an underground network aimed at fomenting discontent in the former Soviet country. It accused a number of foreigners, including a French diplomat and an OSCE official, of playing a role.
"Turkmenistan's officials are still reported to suspect a staff member of the OSCE centre in Ashgabat [the Turkmen capital], Mr Benjamin Moreau, to be engaged in illegal activities," Belgian Foreign Minister Karel De Gucht, OSCE chairman, said in a statement.
"I do not understand the Turkmen accusations against Mr Moreau nor the time that is apparently needed to clear his name fully and unambiguously."
The OSCE comprises 56 participating states from Europe, Central Asia and North America, including Ireland.
It has established 18 field offices throughout Europe and Central Asia and aims to serve as an "early warning system" of conflict as well as conflict prevention and crisis management.
It monitors economic, human rights and security and environmental matters.
Turkmenistan, a big natural gas producer, is governed by President-for-Life Saparmurat Niyazov. The country's rights record is poor with dissent firmly cracked down upon. Most opposition activists and journalists have been driven into exile or jailed.
Turkmen officials have not disclosed the accusations against the foreigners.
"Created in January 1999, the OSCE Centre in Ashgabat has ever since carried out its activities in a transparent and accountable manner, in accordance with its mandate," the OSCE statement said.
Mr Moreau's duties involved promoting human rights and meeting Turkmen citizens, some of whom approached him with "human rights-related complaints", said the OSCE.
Turkmen security forces have arrested a number of people in connection with the case, including a local human rights activist, Annakurban Amanklychev, saying he used glasses with a built-in camera to film secret sites.