Syrian authorities have arrested a 78-year-old dissident who is among the last vocal critics of the government inside the country, rights activists in Syria and London said yesterday.

Haitham Maleh, a leading lawyer who spent seven years in jail in the 1980s, was taken to a security headquarters in the Syrian capital on Wednesday and has not been heard from since, they said.

"They do not want anyone, not even an ant, to speak out. We are going back 20 years," one of the activists said.

Mr Maleh had been defending Mohannad al-Hassani, a fellow lawyer who was arrested in July and accused of "weakening national morale" after he called for the release of political prisoners and documented their plight.

The Syrian Human Rights Committee called for Mr Maleh's release and "an end to all forms of arbitrary and despotic arrests".

A former judge, Mr Maleh was awarded the Dutch Geuzen Medal in 2006 for promoting democracy. Banned from leaving Syria, he could not travel to collect the prize, named after Dutch resistance fighters.

Mr Maleh has repeatedly written to President Bashar al-Assad asking him to end a state of emergency imposed when the ruling Baath Party took power in a 1963 coup and banned all opposition.

He has also criticised the Baath Party's takeover of unions in Syria and urged Assad to grant compensation to thousands killed or jailed during the reign of his father Hafez al-Assad from 1970 to 2000.

"The state of emergency has been used to justify everything from closure of medical labs to the execution of thousands of people. It paralyses the nation and only entrenches totalitarianism and repression," Mr Maleh said.

There was no comment from authorities in Damascus on Mr Maleh's arrest.