(CNN) -- Syrian security forces determined to quell a three-month uprising stormed the northern village of Badama, near the Turkish border, a witness and an activist said Saturday.
Units entered the village equipped with at least six tanks, 21 armed personnel carriers, 10 security buses and randomly fired at houses, the Syrian activist said, adding that security forces also closed the road to the village of Khirbet Aljooz.
Two activists said the forces shelled the mountains around Badama, causing a fire that will block refugees and aid.
Jameel Saib, an eyewitness near the Turkish border, told CNN people that displaced Syrians trying to enter Badama to get bread and supplies saw the Syrian forces close roads leading to the border.
If Badama is taken, Syrian refugees who want to escape the violence in their country will have no medicine or clean water, Saib said.
"This is a starvation war they're waging," he said.
Turkish helicopters were flying in the area, Saib said. CNN could not verify on which side of the border the helicopters were operating.
Meanwhile, the British government Saturday advised its citizens to leave Syria immediately and not travel there.
"Those who choose to remain in Syria, or to visit against our advice should be aware that it is highly unlikely that the British Embassy in Damascus would be able to provide a normal consular service in the event of a further breakdown in law and order and increased violent civil disorder," the Foreign and Commonwealth Office said.
Violence in Syria and an offensive in and around the town of Jisr al-Shugur has spurred thousands of people to make their way to the border region. Turkish officials are worried that the crisis could deteriorate and destabilize the area.
The Turkish government said Saturday more than 10,100 Syrians have crossed the border.
About 3,000 more were on the border near Badama, Saib said.
More than 1,100 people may have died since the unrest across Syria began in mid-March after teens were arrested for writing anti-government graffiti in Daraa, according to Amnesty International. The Syrian government has consistently blamed the protest casualties on "armed gangs."
International pressure on the regime continues to grow.
The United States is collecting information on possible war crimes by Syrian security forces amid the crackdown, a senior Obama administration official said Friday.
The White House faces pressure from critics who say the administration has been slow to respond to crackdown on pro-democracy demonstrators.
The administration is lobbying members of the U.N. Security Council to support a resolution on Syria that, as another administration official put it, "would send a strong message to President (Bashar) al-Assad."
Actress Angelina Jolie met with Syrian refugees in Turkey on Friday and drew attention to the anguish faced by families -- and families torn apart -- by the violence in Syria.
The refugees are living in four camps managed by Turkey and the Turkish Red Crescent, according to the Office of the United Nations High Commissioner for Refugees.
"The people in this camp have fled in fear for their lives, and many told me they were distraught about the safety of loved ones still in Syria," Jolie said, according to the refugee agency.
CNN's Jill Dougherty contributed to this report.