Security forces in Syria have shot dead at least 17 people around the central city of Hama, a rights group said, as activists called for a day of protest against Russia for backing the regime.
"The toll of victims from the operation mounted by security forces and the army in the Hama area has risen to 17 dead," the Britain-based Syrian Observatory for Human rights told AFP in Cyprus on Monday.
More than 60 people were arrested, it added.
The Observatory also reported a 12-year-old boy killed in Douma, near Damascus, by security forces who fired on a funeral, and a man and his son killed in the central province of Homs in the town of Al-Rastan.
Activists organising anti-regime protests on the ground put the day's death toll at 19.
The latest violence came as pro-democracy activists called for a "day of anger" on Tuesday to protest Russia's support for President Bashar al-Assad, whose regime has waged a deadly six-month crackdown on protesters.
"Do not support the killers," activists urged Russia in a message announcing Tuesday's action posted on The Syrian Revolution 2011, a Facebook page that has been the engine for the revolt.
Russia has blocked attempts at the United Nations to sanction Assad's regime and is promoting a separate draft resolution that simply calls on the government and the opposition to open direct talks.
Russian President Dmitry Medvedev on Monday defended the Syrian regime against sanctions for its crackdown, warning visiting British Prime Minister David Cameron of the dangers of such a move.
Cameron met Medvedev in Moscow for talks focusing on Syria and bilateral disputes as global frustration mounted with Russia's continued support for its ally.
A visiting Assad aide said 1,400 people -- half of them Syrian security and army forces -- had died in violence since the demonstrations erupted in mid-March.
However, UN High Commissioner for Human Rights Navi Pillay said Monday 2,600 people have been killed in the crackdown.
The president of the UN Human Rights Council has appointed three experts to examine human rights violations in Syria, as mandated during an August emergency session.
A council source said it would take "at least a month" before investigators go to Syria.
France has been among those to have accused Assad's regime of crimes against humanity. On Monday, the foreign ministry in Paris said the UN Security Council's inability to approve a resolution on Syria was "a scandal."
"How long will the international community remain blind and dumb in the face of this endless sequence of crimes? That's the question we're asking today," said French foreign ministry spokesman Bernard Valero.
But Medvedev refused to give any ground.
He insisted the Kremlin was ready to put more pressure on Assad and argued his differences with the West were "not dramatic".
Yet he also stressed any punitive actions should be applied to both sides equally because the opposition was continuing to reject calls to engage in direct talks.
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"This resolution must be strict, but it must not lead to the automatic application of sanctions," Medvedev said in reference to action proposed by Western powers.
Medvedev's push for dialogue was undermined by an Assad adviser in Moscow who appeared to reject the idea of establishing contacts with the opposition.
"Is there any party in Syria with which (Russia) could mediate?" asked Assad media adviser Bouthaina Shaaban. "There is no such party."
Hours later, Syrian dissident spokeswoman Basma Qadmani's announced the opposition would on Thursday present a list of candidates for a "national council" similar to the one formed in Libya.
Medvedev's tough talk and lack of progress on the ground left Cameron to acknowledge the two sides had failed to bridge their gap on Syria.
"Clearly, Britain would like to go further," said Cameron. "We do not see a future for Assad."
But he also conceded a UN resolution may have to be abandoned in favour of a "clear statement about what is happening in Syria".
Later Monday, the United States made it clear it wanted tougher UN action against Syria.
"We believe that it's time for the UN Security Council to take stronger action," State Department spokeswoman Victoria Nuland told reporters.
"We continue to consult in New York. We want a resolution that has sanctions (with) teeth," she said.
The US "strongly disagreed" with Medvedev's comments Monday, she added.
Britain and France have been leading the diplomatic offensive against Assad, and Paris issued another barb at what it called some nations' indifference to the bloodshed.
The UN resolution Russia is blocking would most likely affect arms sales -- the one area left untouched by the powerful economic sanctions imposed already by the European Union and the United States.
Switzerland followed suit on Monday by widening its travel and financial embargo against Assad's regime to 19 individuals and eight institutions.
But Russia, keen to preserve some $4 billion in current and future Syrian arms contracts, has taken more assertive steps in trying to persuade Assad to adopt political improvements that could help him keep his hold on power.
His aide Shaaban said after talks with the upper house of parliament's foreign affairs chief Mikhail Margelov that Syria favoured the cautious reform process seen in Russia since the Soviet Union's collapse.
"In the past 20 years, Russia has undergone various processes that led to structural changes," she said.
"We want things in Syria to develop the way they did in Russia, in a bloodless manner."
Margelov said he had received Assad's approval to send a group of Russian senators to Damascus and other Syrian cities to independently report on the situation on the ground.