The Council of Europe has awarded its Václav Havel human rights prize to the Iraqi activist Nadia Murad, who was an Islamic State sex slave before becoming the face of a campaign to protect her Yazidi people.

The award, which honours outstanding civil society action in defence of human rights, comes with prize money of €60,000 (£54,000).

The slight, softly spoken woman was taken by Isis from her home village of Kocho near the northern Iraqi town of Sinjar in August 2014 and brought to the city of Mosul. Among the first things Isis forced on her was to disavow her Yazidi faith, an ancient religion with more than half a million adherents concentrated near the Syrian border in northern Iraq.

As a captive of the reviled extremist group, Murad, 23, said she was tortured and raped for three months until she managed to escape and flee to Germany.

She has since become a human rights activist, bringing the plight of the Yazidi community, especially the forced sexual enslavement and human trafficking of women and children captured by Isis, to the forefront of international attention.

Murad, in her acceptance speech in Strasbourg, called for the creation of an international court to judge crimes committed by Islamic State jihadists. She recalled the plight of some 12,000 Yazidis who have fallen victim to Isis persecution, branding it a “genocide”.

“The free world is not reacting,” said Murad, 18 of whose family members have been either killed or enslaved by Isis.