Beirut ? Syrian security forces fired on thousands of protesters Friday, killing a teenage boy and at least 15 other civilians as accounts emerged of more indiscriminate killing and summary executions by the autocratic regime of President Bashar Assad, activists said.

The three-month uprising has proved stunningly resilient despite a relentless crackdown by the military, the pervasive security forces and pro-regime gunmen. Human rights activists say more than 1,400 Syrians have been killed and 10,000 detained as Assad desperately tries to maintain his grip on power.

“What is our guilt? We just demanded freedom and democracy nothing else,” said Mohamed, 27, who spoke to The Associated Press from a refugee camp in neighboring Turkey where nearly 10,000 Syrians have fled.

Mohamed, who asked to be identified only by his first name for fear of reprisals, and other refugees offered harrowing accounts of the regime’s bombardment.

“I saw people who were beheaded with machine-gun fire from helicopters” and a man tortured to death when security forces poured acid on his body, he said.

He said a sugar factory in Jisr al-Shughour was turned into a jail where they “hold quick trials and execute anyone who they believe participated in protests.” Jisr al-Shughour was a town that was spinning out of government control before the military recaptured it last Sunday.

U.N. envoy Angelina Jolie traveled to Turkey’s border with Syria on Friday to meet some of the refugees, and she was greeted by a 45-foot-long banner that read: “Goodness Angel of the World, Welcome” in English and Turkish. Police prevented media coverage of the visit.

Assad is expected to give a speech as early as Sunday in what would be only his third public appearance since the uprising began in mid-March, inspired by the revolutions sweeping the Arab world.

The uprising has proven to be the boldest challenge to the Assad family’s 40-year dynasty in Syria. Assad, now 45, inherited power in 2000, raising hopes that the lanky, soft-spoken young leader might transform his late father’s stagnant and brutal dictatorship into a modern state.

But over the past 11 years, hopes dimmed that Assad was a reformist at heart. Now, as his regime escalates a brutal crackdown, it seems increasingly unlikely that he will regain any political legitimacy.

On Friday, a French official said the European Union was preparing new, expanded sanctions that would target “economic entities” in Syria.

France, Britain, Germany and Portugal are also sponsoring a draft resolution at the U.N. Security Council to condemn Syria. They say they have the votes needed to pass it but want more support.

Syria’s foreign minister, Walid al-Moualem, told the Security Council in a letter circulated Friday that the proposed resolution is based on erroneous information and would intrude in Syria’s internal affairs.

The resolution, he added, would help the “extremists and terrorists” he blamed for the country’s violence.

Despite widespread calls for an end to the crackdown, the country’s future is far from certain — particularly as there is no clear alternative to Assad.

Syria has a pivotal role in nearly every thorny Mideast issue. A staunch Iranian ally, Syria backs the militant groups Hezbollah in Lebanon and Hamas in the Gaza Strip. It has also provided a home for some radical Palestinian groups and has exerted influence in neighboring Iraq.

Chaos in Syria, as a result, has wide implications on the region.

Syria has tried to exploit those fears, alleging that armed gangs and foreign conspirators are behind the unrest, not true reform-seekers. In what has become a weekly back-and-forth between activists and the government, both sides offered divergent death tolls.

Syria’s state-run TV said Friday that a policeman was killed and more than 20 were wounded when “armed groups” opened fire at them. It added that six police officers were wounded in Deir el-Zour when gunmen attacked a police station in the area.