Haissam Maleh said the travel ban was linked to a speech on the human rights situation in Syrian he made in the German parliament last December.

Mr Maleh is a lawyer and chairman of the Syrian Human Rights Association.

He is among the 1,500 intellectuals who on Tuesday signed a petition urging President Basher al-Assad to introduce political reform.

Speaking to the BBC Newshour programme, Mr Maleh said officials took his passport at Damascus airport when he was about to board his flight to the United Arab Emirates and told him he could not leave the country.

He said he knew that the order for the ban came from the Syrian secret police who he met with on Tuesday to answer questions regarding the lecture he made in Germany.

Mr Maleh said the secret police objected to his speech where he connected the issue of human rights and the current situation in Syria.

The ban comes as a Lebanese newspaper on Tuesday published a petition by other activists, lawyers and intellectuals which calls for the release of all political prisoners and the lifting of the state of emergency in place since 1963.

Mr Maleh said the government had problems with the Human Rights Association, accusing it of interference.