The United States has accused the authorities in Syria of creating a humanitarian crisis by refusing to allow aid to be delivered in regions affected by a security crackdown aimed at quelling anti-government protests.
"Syrian leaders have no excuse for denying humanitarian assistance by a neutral body like the ICRC [International Committee of the Red Cross]," the White House said in a statement on Saturday.
"If Syria's leaders fail to provide this access, they will once again be showing contempt for the dignity of the
Syrian people," the statement added.
The United Nations and the European Union also voiced grave concerns over the events in Syria.
While UN chief Ban Ki-moon deplored the mounting death toll, Catherine Ashton, the European Union foreign policy chief, echoed US concerns and called on Syria to allow international aid agencies in to help civilians caught up in the increasing violence.
"I deplore the escalating use of brutal force against protesters in Syria in recent days," Ashton said in a statement. "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 [Bashar al] Assad.
"Those responsible for the violence and killings must be held accountable," said Ashton, calling for Damascus to comply with UN requests to co-operate with its human rights officials.
Ashton also called for Syria to lift its siege of cities where protests had taken place.
The comments came as thousands of Syrians continued to flee to Turkey to escape violence and unrest.
A senior Turkish diplomat said 4,300 Syrians had crossed the border as of Saturday morning and that Turkey was prepared for a further influx.
"Turkey welcomed a great many number of guests in the past in their times of most dire need. We can do that again," Foreign Ministry Deputy Undersecretary Halit Cevik was quoted as saying by state-run Anatolia news agency.
Most of those fleeing come from the town of Jisr al-Shughur and nearby villages, where Syrian troops backed by tanks, helicopters and heavy armour have been operating for several days.
In the Turkish border town of Yayladagi, authorities set up four field hospitals, each with a 10-bed capacity, for emergency cases, the semi-official Anatolia news agency said.
Most of the nearly 50 Syrians, who were wounded in clashes in Jisr al-Shughur or elsewhere recently, were being treated at the state hospital in the Turkish city of Hatay.
One of them, who only identified himself with his first name, Ahmad, told an Associated Press reporter at his hospital bed on Saturday that he was hit by three bullets during a protest in Jisr al-Shughur last Saturday.
"The snipers suddenly started firing onto us from three buildings," a Turkish relative quoted him as saying in Arabic. "I was hit in the neck and chest first but a third bullet found my right arm when I raised it while on the ground.''
The Syrian crackdown on anti-government protests has drawn global condemnation, but Damascus has rejected all criticism.
It has warned the United Nations that a European draft resolution condemning the country for the crackdown would only embolden "extremists and terrorists".