Activists claim that up to 30 people have been killed in Syria where thousands have taken to the streets for another day of anti-government rallies, dubbed a "day of defiance".
Human rights group Insan said that at least 16 people had been killed in the central city of Homs, six in Hama and two in Jableh. It said the total death toll was 26 but didn't specify where the other two deaths occurred.
A human rights activist told the Associated Press news agency that 30 people had died, while Syrian state television said an army officer and four police were killed in Homs by a "criminal gang".
Security forces killed four protesters in the city of Deir al-Zor, a local tribal leader told Reuters.
Al Jazeera could not independently verify the reports because of restrictions on reporting in the country.
Activist Najati Tayara said security forces opened fire to disperse protests that broke out after noon prayers in Homs.
"We were chanting 'The people and the army are one' and 'The people want to topple the regime'," a witness told Al Jazeera over the phone. "Then security and thugs opened fire."
The sound of continuous gunfire was audible over the phone, as well as people shouting "There are snipers on the rooftops".
There were also reports that live ammunition had been fired in the Damascus suburb of Tel, wounding several protesters.
Reem Haddad, a spokeswoman for the Syrian information ministry, denied in a phone interview with Al Jazeera that she had any knowledge that Syrian protesters had been killed on Friday.
She said a planned visit by a UN delegation aimed at investigating the situation in Syria would be a positive thing for the government.
"The Syrian government is not worried, because there is nothing wrong," Haddad said.
UN secretary-general Ban Ki-moon said on Friday that Syria had agreed to allow UN teams to enter the country and check the humanitarian situation there.
In an emergency session on Friday, the UN's top human rights body voted to condemn Syria for using deadly force against protesters and launched an investigation into the situation.
Al Jazeera speaks to an exiled Syrian activist about how information is reaching the rest of the world
"With today's vote, the Council has stood against attempts to silence dissent with the use of gratuitous violence, which is not the act of a responsible government," said Susan Rice, U.S. ambassador to the United Nations in New York.
The military earlier deployed troops and tanks in flashpoint cities including Baniyas, Homs and Rastan and in some Damascus suburbs.
In the Damascus district of Midan, protesters marched chanting "To heaven we go, one million martyrs".
The daughter of prominent opposition leader Riad Seif said her father had been arrested during the demonstration along with several others.
"Around 1:30pm, someone told me that my father was arrested at the al-Hassan mosque," Jumana Seif told Al Jazeera. "A friend told me later that he [Riad] had been hit on his head by the security elements."
She said her father had been participating in rallies in Midan every Friday since protests there began.
A 64-year-old former MP, Seif had been imprisoned twice since 2001, serving in total more than seven years in jail, for seeking reforms and constitutional changes in Syria.
'Will never stop'
Huge crowds were rallying in the coastal city of Baniyas, where there was a heavy army presence.
"We are here today to say we don't want to die. We don't want to be humiliated and we will never stop," a protester told Al Jazeera.
"Killing us and invading us with tanks will never stop us. Our souls will ascend to heaven calling for freedom".
"Killing us and invading us with tanks will never stop us. Our souls will ascend to heaven calling for freedom"
Protester in Baniyas
In the mainly Kurdish town of Amuda in the northeast, people were chanting "The Syrian people are one" and "Freedom, freedom, peaceful, peaceful".
More than 1,000 people have reportedly been arrested in the last week.
The army announced on Thursday that its forces had begun to pull out of Deraa, the southern city which has been under military siege since April 25.
General Riad Haddad, the military's political department chief, initially said all troops would be out of the city by Thursday night, but on Friday he said the withdrawal was gradual.
"Throughout the night, they withdrew ... and this is continuing today," he told AFP. He said 600 people had been arrested in Daraa during 11-day operation.
Activists said the city remained under the army's control and was surrounded by tanks. Footage emerging from the city showed massive destruction, with shelled buildings and burnt cars.
Activists say scores of civilians were killed during the siege and that a severe humanitarian crisis had emerged, with shortages of bread, water and gas.
President Bashar al-Assad is under growing international pressure to end the violent crackdown on protesters.
The European Union on Friday agreed to impose sanctions on 14 Syrian officials involved in the crackdown, although Assad was not among those immediately targeted. But an official said further consideration would be given to the inclusion of "the highest level of leadership" in the coming days.
If no member state objects over the weekend, the sanctions will formally be approved on Monday and are expected to be made law on May 10.
The United States and its international partners will take "additional steps" against the Syrian government unless it stops killing and harassing its people, the White House said on Friday.
"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," he said.
"In this context, the United States welcomes today's decision by the European Union to impose sanctions on Syrian regime officials responsible for human rights abuses in Syria," Carney said. The United States last week imposed sanctions of its own against some figures in the Syrian government.
Aid workers from the Red Cross and Red Crescent delivered their first emergency relief supplies to Deraa on Thursday, according to a spokesperson for the organisation.
Hicham Hassan said a convoy of two lorries carrying clean drinking water and two more with food and first-aid material accompanied a team of 13 experts from the Syrian Red Crescent and International Committee of the Red Cross.
In-depth coverage of escalating violence across Syria
Rights campaigners say army, security forces and assailants loyal to Assad had killed at least 560 civilians during seven weeks of pro-democracy demonstrations.
The authorities blame "armed terrorist groups" for the violence, including the killings of civilians and members of the security forces. Assad says protests are part of a foreign conspiracy to cause sectarian strife.
Dorothy Parvaz, an Al Jazeera journalist, has been detained since she flew in to Damascus one week ago. The network and her family are calling for her immediate release.