Updated

U.S. Secretary of State John Kerry is ramping up criticism of Syrian President Bashar Assad, calling him a "one-man super-magnet for terrorism" who could be responsible for the disintegration of Syria.

Speaking a day after he told an international peace conference for Syria there's no way Assad could play a role in a potential transitional government, Kerry said Thursday that Assad must act in the best interests of his country and accept that his family's long reign over Syria is over. In an interview with al-Arabiya television, Kerry said Assad's actions had not only killed thousands of his people over the past three years, but were putting them at further risk from extremists.

Kerry said — quote — "more and more terrorists keep coming" to Syria "because Assad keeps killing."