Syrian security forces arrested hundreds of activists and anti-government protesters in house-to-house raids across the country Monday, part of an escalating government crackdown aimed at stamping out a revolt engulfing the country.
The government's punishing response triggered new international sanctions Monday, as the European Union imposed an arms embargo.
The measure, which followed US sanctions, also prohibits 13 Syrian government officials from travelling anywhere in the 27-nation EU and freezes their assets.
The United Nations said a humanitarian mission had not been allowed access to the southern city of Daraa, which has been cut off for the past two weeks after Syrian forces put down anti-government demonstrations.
UN humanitarian chief Valerie Amos said the aid mission has been postponed until later this week.
She said she has been trying to find out why the mission was not allowed into Daraa Sunday as scheduled.
UN spokesman Farhan Haq said Monday that Syrian President Bashar Assad had indicated a "willingness" to give the humanitarian mission access to Daraa during a telephone conversation last week with Secretary-General Ban Ki-moon.
Assad has dispatched army troops and tanks to crush the seven-week uprising that has posed the most serious challenge to his family's 40-year rule.
Assad's regime appears determined to crush the uprising by force and intimidation, despite the rapidly growing international outrage and a death toll that has topped 630 civilians since the unrest began, according to rights groups.
Monday's arrests, which zeroed in on the protests' organisers and participants, were focused in four areas — the central city of Homs, the coastal city of Banias, some suburbs of the capital Damascus and villages around the southern flashpoint city of Daraa, said Rami Abdul-Rahman, director of the Syrian Observatory for Human Rights.
He and other activists said the crackle of gunfire could be heard in the Damascus suburb of Maadamiyeh.
Activists said security forces redeployed in the town Monday after a brief withdrawal the day before, closing all roads leading in.
The area, scene of large demonstrations in past weeks, was without electricity, communication or water, the activists said on condition of anonymity for fear of reprisal.
Residents also reported house-to-house raids and arrests and said several tanks were stationed in the town.
By early afternoon, scores of women were demonstrating in Banias, demanding the release of hundreds of detained men who were being held at the city's soccer stadium, Abdul-Rahman said.
He added that security officers promised the women that all men over the age of 40 would be freed.
In an indication that the regime shows no sign of folding, Assad was quoted as saying in comments published Monday that "the current crisis in Syria will be overcome and that the process of administrative, political and media reforms are continuing."
The report, in the private daily Al-Watan, which is close to the government, did not elaborate but said Assad made the comments while receiving a local delegation Sunday.
The European Union said Monday it was banning the shipment to Syria of "arms and equipment that could be used for internal repression."
In an attempt to increase the pressure on Assad's regime, the United States has also imposed sanctions. Those penalties target three senior Syrian officials as well as Syria's intelligence agency and the Revolutionary Guard in Iran, a key Syrian ally.
Abdul-Rahman said that more than 250 people had been arrested in Banias, which is home to one of Syria's two oil refineries.
Special forces backed by tanks entered the city Saturday.
Among those arrested was a leading organiser of the demonstrations, along with his father and three brothers.
Security forces also detained Firas Khaddam, nephew of former Vice President Abdul Halim Khaddam, who has been living in exile since he left Syria in 2005 and called for the overthrow of the regime, Abdul-Rahman said.