Syrian security forces 'kill dozens Hama'
Shells and gunfire from Syrian security forces have killed at least 33 people in the city of Hama, activists say.
Dozens have reportedly also been injured in two northern districts.
EU foreign ministers meanwhile imposed a new round of sanctions, banning the export of luxury products and goods that could be used to repress dissent.
UK Foreign Secretary William Hague said Damascus was "not in full compliance of the ceasefire requirements" of the peace plan negotiated by Kofi Annan.
On Sunday, Mr Annan described as a "pivotal moment" the UN Security Council's decision to deploy up to 300 observers to Syria.
"The government in particular must desist from the use of heavy weapons and, as it has committed, withdraw such weapons and armed units from population centres and implement fully its commitments under the six-point plan," Mr Annan, the UN and Arab League envoy to Syria, added.
A UN Supervision Mission to Syria (UNSMIS) advance team arrived in the country in the past week and over the weekend visited the central city of Homs, which has been under almost constant bombardment since the ceasefire began 10 days ago.
Opposition and human rights activists said government tanks and artillery opened fired on the Arbaeen and Mashaa al-Arbaeen districts of Hama, which lie to the north of the city centre, on Monday morning.
"It began in the morning with tanks and artillery, there were houses burning," a local activist called Mousab told Reuters news agency by telephone. "[Then] the military forces entered and shot people in the street."
The UK-based Syrian Observatory for Human Rights said 33 people had been killed in Hama on Monday. The Local Co-ordination Committees, an activist network, put the death toll at 35.
Another activist living in a neighbouring district said he could see a thick column of smoke rising from areas where the shells had been landing.
Earlier, Syrian state television reported that observers had visited Zabadani, a town in the mountains north-west of Damascus. A UNMIS spokesman said the team also planned to travel to the suburbs of Douma and Harasta.
An activist in Zabadani, Fares Mohammed, said the UN team had been in the town for only about 30 minutes, had talked to a few people and seen some buildings damaged by what he said were government attacks.
Army tanks deployed in the town centre had been withdrawn shortly before the visit and hidden less than 1km (0.6 miles) away, he added.
"Those tanks can be back in the city in two minutes," he told the Associated Press.
But in Homs, the continued presence of two observers appears to have led to a significant reduction in violence in recent days.
"Before, we were getting hit with rockets and mortars," activist Abu Mohammed Ibrahim told AP. "Now there are snipers and some gunfire, but only medium weapons. Before they fired all they had at us."
Meanwhile, state media reported that "terrorists" had killed a doctor and two military officers in the country's south, and another two officers in Hama province.
In a separate development, a Jordanian relief agency said Syrian troops had attacked about 900 people trying to flee over the border near the Jordanian town of Ramtha early on Sunday.
Kitab and Sunna spokesman Mohammed Ahmed Iyad told the BBC that about 195 Syrians had been injured by gunfire.
The refugees told him that Syrian forces had arrested dozens among their group. There was also noticed an influx of unaccompanied children, sparking fears that their parents and relatives had been detained or died.
The UN says about 9,000 people have died since pro-democracy protests began in March 2011. In February, the Syrian government put the death toll at 3,838 - 2,493 civilians and 1,345 security forces personnel.
'Keeping up pressure'
Monday's fresh violence came as diplomats said the EU's Council of Foreign Ministers had agreed a 14th round of sanctions.
EU experts will work out over the next few weeks precisely which products will be affected by the new embargoes.
So-called "dual-use" goods, which could be used for repression, could reportedly include anything from vehicles to fertilisers. A ban on luxury goods imposed on North Korea included caviar, truffles, expensive wines and spirits, fashion accessories, perfumes, crystal and silverware and thoroughbred horses.
Diplomats told AFP news agency that the luxury goods ban represented a symbolic blow against President Bashar al-Assad and his wife, Asma, whose apparently expensive tastes have been widely criticised.
Last month, Asma al-Assad, who was born in the UK, was hit with a travel ban and her assets in the EU were frozen. The Syrian leader's mother, sister and sister-in-law were also targeted.
UK Foreign Secretary William Hague said on Monday: "It is very important for us to keep up that pressure, step up that pressure. They are not in full compliance of the ceasefire requirements of the Annan plan."
But Russia's foreign ministry condemned the new sanctions, saying they were "unacceptable from the point of view of international law".
Later, US President Barack Obama signed an executive order intended to prevent the authorities in Syria and Iran from using sophisticated communications equipment against dissidents.
Mr Obama said the two countries were conducting violent campaigns against their own people, assisted by "the malign use of technology".