Brussels: Expressing concern over humanitarian crisis, European Union Foreign Policy Chief Catherine Ashton has requested Syria to let international aid agencies help civilians caught up in the increasing violence there. 

In a statement denouncing Syria's crackdown on pro-democracy protesters Saturday, she echoed US concerns about the humanitarian crisis the conflict had created and repeated her calls for the regime to change course.

"I am deeply concerned by the worsening humanitarian situation caused by the actions of the Syrian authorities and call upon them to allow immediate and unhindered access to international human rights monitors and humanitarian agencies, such as the International Committee of the Red Cross," she said.

Her statement came as harrowing eyewitness accounts came in Saturday of Syrian forces backed by helicopter gunships attacking protesters, as President Bashar al-Assad continued his crackdown despite an international outcry.

"I deplore the escalating use of brutal force against protestors in Syria in recent days," Ashton said. "I reiterate my repeated calls on the Syrian authorities to change course.

"This includes releasing all those arrested in connection with protests, as well as other political prisoners who remain under detention despite the recent amnesty announced by President Assad.

Ashton also called for Syria to lift its siege of cities where protests had taken place.

The reported death toll mounted yesterday as detailed accounts emerged from some of the thousands of refugees who fled to Turkey from bloodshed in the northwestern town of Jisr al-Shughur.

Syrian army deserters who have fled to Turkey have told of atrocities committed by soldiers in suppressing protests, under threat of execution if they disobeyed orders.

"Those responsible for the violence and killings must be held accountable," said Ashton, calling for Damascus to comply with UN requests to cooperate with its human rights officials.