A Syrian opposition group says explosions in the province of Daraa killed 20 people Tuesday, as shelling and heavy fighting was reported throughout the country.

The Britain-based Syrian Observatory for Human Rights told VOA by phone that there were “clashes and bombardments in almost every province,” from Daraa in the south to Aleppo in the north. A spokesman, Mataz Suheil, reported heavy shelling in the western side of Aleppo city and five unidentified bodies found in the Zahra district.

Syria's state-run SANA news agency said Tuesday the military had killed a group of terrorists and destroyed “explosives factories” in Aleppo.

One Kurdish militia member was killed by Turkish troops firing across the border Tuesday. Another opposition group, the Local Coordination Committees, said Syrian government forces were blasting rebel strongholds outside Damascus.

Meanwhile, Russia urged NATO not to intervene in the Syrian conflict or set up buffer zones between government forces and opposition fighters.

In Moscow Tuesday, Russian Deputy Foreign Minister Gennady Gatilov called on NATO members not to “seek pretexts” for military intervention or “introduce initiatives such as humanitarian corridors or buffer zones.”

Russia and China have vetoed three U.N. Security Council resolutions condemning Syrian President Bashar al-Assad's crackdown against unrest.

The Lebanese newspaper Al-Diyar reported Tuesday that Mr. Assad flew by helicopter from Damascus to battle-torn Aleppo as he ordered about 30,000 more troops into the battle there. The report has not been confirmed by Syrian media and opposition activists told VOA they could not verify it.

The Syrian Observatory reported that 210 people were killed across Syria a day earlier. It says five officers were among the 40 government troops killed Monday, an unusually high death toll for troops, which the Syrian Observatory says demonstrates the conflict's escalation.

A U.N. spokesman Monday said U.N. Secretary-General Ban Ki-moon appealed to Syrian Foreign Minister Walid al-Moualem for the government to “show compassion to its own people.” The two met on the sidelines of the U.N. General Assembly in New York.

During a speech to the General Assembly, Moualem accused the United States, France, Qatar, Saudi Arabia and Turkey of supporting “terrorism” in Syria by providing arms and money. He also characterized calls for Mr. Assad to step down as “blatant interference” in Syrian domestic affairs.