A law passed by the Tunisian parliament this week is designed to silence government critics and human rights activists, Amnesty International has warned.

The organization said that amendment to Tunisia's penal code, which deals with violations of "external security" is intended to target human rights activists who lobby foreign bodies such as the European Union (EU), to put pressure on the government over its human rights record.

"Instead of cleaning up their dismal human rights record, the Tunisian authorities have elected to further criminalize human rights advocacy and to undermine the courageous work done by human rights defenders and others seeking to expose the violations that take place in Tunisia on a daily basis," said Amnesty International.

The amendment to Article 61bis of the Penal Code criminalizes contacting "agents of a foreign power to undermine the military or diplomatic situation in Tunisia". Those convicted of this crime face up to 20 years in prison, with a minimum sentence of five years.

The new legislation also criminalizes those who contact foreign organizations in order to harm Tunisia's vital interests, including "economic security".

This law appears to be a direct response to meetings held in May by Tunisian human rights activists with EU parliamentarians and officials, in Madrid and Brussels.

During the meetings, the Tunisian activists urged them to pressure the government to uphold its international human rights obligations.

The new law also adds to existing drastic restrictions on human rights defenders and freedom of expression and association by targeting those seek to speak about Tunisia's human rights record to foreign bodies.

Activists in Tunisia face harassment and intimidation. Many have reported being under constant surveillance by the security forces, and have also reported being prevented from travelling abroad or within the country, in breach of the right to freedom of movement.

Many have also reported being beaten up, reportedly by men in civilian clothes who appeared to be agents of the security forces.

Tunisian activists who have spoken out against the authorities' human rights record while abroad have been harassed and interrogated upon their return to Tunisia. Several have been denied permission to travel abroad again.

Amnesty International has urged the EU and its member states to robustly respond to such a cynical move and put pressure on the Tunisian government to fulfil its human rights obligations.

"The Tunisian authorities must repeal all provisions in Tunisian law which criminalize the peaceful exercise of the rights to freedom of expression, association and assembly," said Amnesty International.