US Secretary of State John Kerry on Sunday warned the regime of President Bashar al-Assad and its allies including Russia against exploiting the fragile ceasefire in Syria for their own means.

"If the regime and its backers think they can test boundaries, diminish their compliance in certain areas, or act in ways that call into question their commitment to the cessation -- without serious consequences for the progress we have made -- they are mistaken," Kerry said after talks with his European allies in Paris.

Kerry said 600 fighters from the Islamic State group had been killed in Syria in the past three weeks.

"In Syria, over the last three weeks alone, Daesh has lost 3,000 square kilometres (1,160 square miles) and 600 fighters," Kerry said, using another name for Islamic State.

Source: AFP