Syria's restive central province of Homs came under intense shelling by government forces Tuesday, with activists reporting at least 56 victims in what was described as one of the worst crackdowns on anti-regime protesters since February 4, dpa reported.
Activists said some 300 shells were fired against the city and the surrounding province's most rebellious areas.
Omar Homsi, who is based in Homs, told dpa by phone that most of the victims were injured people who later died when "thugs loyal to (President Bashar) al-Assad" targeted the only make-shift clinic in the Baba Amr region, where the wounded had been taken.
At the same time, activists said the opposition Free Syrian Army, composed mostly of army defectors, had managed to foil two attempts by government troops to storm Baba Amr.
Several shells landed near the Lebanese northern border, wounding at least 10 people there, Homsi added.
"The Syrian army is preparing to storm some regions in Homs," the head of the London-based Syrian Observatory for Human Rights told dpa.
A spokesman for the International Committee of the Red Cross (ICRC) in Damascus said the organization was exploring ways of delivering urgently needed aid, including through "a cessation of fighting in the most affected areas."
Meanwhile, two Iranian warships suspected of having delivered weapons to the Syrian regime left the Syrian coastal town of Tartous and headed back to Iran through Egypt's Suez Canal, a source at the strategic waterway told dpa on Tuesday.
Syrian opposition activists based in Lebanon said the warships, which arrived in Tartous at the weekend, had delivered "sophisticated weapons and tapping equipment to help the Syrian authorities trace activists and opposition figures."
On the diplomatic front, Russia said it would not take part in a forthcoming meeting of Western and Arab nations, which it says will push for regime change. However, Russia said it was in favour of having the United Nations step in to resolve the humanitarian situation in the country.
The "Friends of Syria" conference is scheduled to be held in Tunisia on Friday. Representatives of the government in Damascus have not been invited.
Russia and China vetoed a resolution condemning the Syrian regime in the UN Security Council on February 4.
Russia, which is a major arms supplier to Syria, has long opposed efforts to condemn the government of al-Assad, saying they would represent a step towards a Libya-style military intervention.
Both the Syrian opposition and the government should reject violence, and "all parties" in the country's conflict should be present at the conference table," Russian Foreign Ministry spokesman Aleksandr Lukashevich said.