By Khaled Yacoub Oweis

AMMAN (Reuters) – The United States, reacting to the killing of 27 protesters by Syrian security forces on Friday, threatened to take new steps against the Syrian government unless it stopped killing and harassing its people.
Rights campaigners said the dead were among thousands of protesters who demonstrated after Friday prayers in cities across the country, from Banias on the Mediterranean coast to Qamishly in the Kurdish east, demanding an end to President Bashar al-Assad's rule.

The European Union agreed to impose sanctions in response to Assad's violent crackdown on protesters, which rights campaigners say has killed more than 580 people.
"The United States believes that Syria's deplorable actions toward its people warrant a strong international response," White House press secretary Jay Carney said in a statement.
"Absent significant change in the Syrian government's current approach, including an end to the government's killing of protesters ... the United States and its international partners will take additional steps to make clear our strong opposition to the Syrian government's treatment of its people."

The United States imposed sanctions of its own last week against some figures in the Syrian government.
Friday's bloodiest confrontation was in the city of Homs where 15 protesters were killed, activist Ammar Qurabi said.
State television said an army officer and four police were killed in Homs by a "criminal gang," though another activist, Wissam Tarif, said witnesses told him nine soldiers defected in Homs to the protesters and may have clashed with other troops.

Four protesters were killed in Deir al-Zor, said a local tribal leader from the region which produces most of Syria's 380,000 barrels per day of oil. They were the first deaths reported there in seven weeks of nationwide unrest.
International criticism has mounted against Assad, who has gone on the offensive to maintain his family's four-decade grip on power in the country of 20 million and crush demonstrators demanding freedom.
European Union governments agreed on Friday to impose asset freezes and travel restrictions on up to 14 Syrian officials responsible for the violent repression.
Officials blame "armed terrorist groups" for the violence, give a lower death toll and say half the fatalities have been soldiers and police. They say demonstrators are few in number and do not represent the majority of Syrians.
Assad himself was not targeted by the sanctions, which follow last week's EU agreement in principle to impose an arms embargo on Syria. The measures will be approved on Monday if no member state objects.

Assad's security forces and troops, which stormed the city of Deraa last week, have prevented demonstrators establishing a platform such as Egypt's Tahrir Square by blocking access to the capital Damascus. But every week protesters have used Friday prayers to launch fresh marches.
"The people want the overthrow of the regime," shouted 2,000 demonstrators in the Damascus suburb of Saqba.
Footage released on the Internet and aired on Al Jazeera television showed protesters in several towns and cities echoing the same calls for freedom and change of leadership.
"7,000 ARRESTED"
In Hama, where Assad's father brutally suppressed an armed Islamist uprising in 1982, a rights activist said security forces shot dead six demonstrators.
The London-based Syrian Observatory for Human Rights said a protester was killed in Latakia and three were wounded.

Despite the harsh crackdown, protesters appear determined to maintain demands for an end to years of repression, arrests without trial and corruption by the ruling elite.
"The Syrian people will not back down after the country's budding youths were killed in their hundreds," said Montaha al-Atrash of the Syrian human rights organization Sawasiah.
Opposition leader Riad Seif, who helped initiate a peaceful movement seeking political freedoms and democracy 10 years ago, was arrested at one of Friday's protests, his daughter said.
On Thursday authorities arrested prominent Damascene preacher Mouaz al-Khatib, a major figure in the uprising, rights campaigners said on Friday.
A Western diplomat said 7,000 people had been arrested since the demonstrations broke out on March 18 in Deraa.
DERAA "SIEGE"

Last week, Assad ordered the army into Deraa, cradle of the uprising that began with demands for greater freedom and an end to corruption and is now pressing for his removal.
An ultra-loyalist division led by his brother Maher shelled and machinegunned Deraa's old quarter on Saturday, residents said. The United States condemned the assault as "barbaric."
Syrian authorities said on Thursday the army had begun to leave Deraa, but residents described a city still under siege.

Human Rights Watch cited figures from Syrian rights groups saying 350 people had been killed there.
(Additional reporting by Yara Bayoumy and Mariam Karouny in Beirut, Suleiman al-Khalidi in Amman, Adrian Croft in London, Luke Baker, David Brunnstrom and Ilona Wissenbach in Brussels; Writing by Dominic Evans; editing by Tim Pearce)