UN chief Ban Ki-moon has expressed “increasingly grave concern” at the bloody crackdown on protesters in Syria, especially at the use of tanks and live ammunition by security forces.

UN chief Ban Ki-moon has expressed “increasingly grave concern” at the bloody crackdown on protesters in Syria, especially at the use of tanks and live ammunition by security forces.

“Syrian authorities have an obligation to protect” civilians, Ban told journalists in New York as the UN Security Council held formal consultations on a statement condemning the deadly violence.

Security forces firing live rounds and tear gas have killed at least 400 people since March 15, activists say, including 25 on Monday alone in the flashpoint town of Daraa. Scores have been arrested.

The United States has said that for now it will limit its response to diplomacy and possible sanctions.

Washington previously ordered non-essential embassy staff out of Syria, which has been shaken by six weeks of protests against President Bashar al-Assad’s autocratic rule.

Britain and France have made calls for “strong” action against the violence by Assad’s forces.

The Security Council issued no statement on Tuesday on Syria but will hold further consultations on Wednesday.