GAZIANTEP, TURKEY - Syria pulled both Turkey and Israel closer to military entanglements in its civil war Monday, bombing a rebel-held Syrian village a few yards from the Turkish border in a deadly aerial assault and provoking Israeli tank commanders in the disputed Golan Heights into blasting a mobile Syrian artillery unit across their own armistice line.

The escalations, which threatened once again to draw in two of Syria's most powerful neighbors, came hours after the fractious Syrian opposition announced a broad new unity pact that elicited praise from the foreign powers backing its effort to topple President Bashar Assad.

There has been speculation that Assad, feeling increasingly threatened, may deliberately seek to expand the conflict that has consumed much of his country for the past 20 months, leaving roughly 40,000 people dead and more than 400,000 refugees in Turkey, Jordan, Lebanon and Iraq. Although there was no indication that Assad was trying to lure Israel into the fight, any Israeli involvement could rally his failing support and frustrate the efforts of his Arab adversaries.

'Here is total chaos'

The attack on the Turkish border, by what witnesses identified as a Syrian MiG-25, demolished at least 15 buildings and killed at least 20 people in the Syrian town of Ras al-Ain, the scene of heavy fighting for days and an impromptu crossing point for thousands of Syrians clambering for safety in Turkey.

"The plane appeared in seconds, dropped a bomb and killed children. Here is total chaos," said Nezir Alan, a doctor who witnessed the bombing.

Speaking from Ras al-Ain, he said the bombing had wounded at least 70 people, 50 of them critically. Turkish television reported that ambulances were rushing victims into Ceylanpinar, Turkey, just across the border, and footage showed people on both sides of the border running in panic, while military vehicles raced down streets as a huge cloud of smoke hung over the area.

There were no immediate reports of any deaths or injuries in Ceylanpinar. But the Turkish authorities, increasingly angered by what they view as Syrian provocations, have deployed troops and artillery units along the 550-mile border with that country and have raised the idea of installing Patriot missile batteries that could deter Syrian military aircraft.

Turkish foreign minister Ahmet Davutoglu sent a diplomatic note to Syria on Monday to protest the Ras al-Ain bombing, the semi-official Anatolian News Agency reported.

In Israel, the military said Israeli tanks that are deployed in the Golan Heights, which the Israelis seized from Syria in the 1967 Arab-Israeli war, had made a direct hit on a Syrian mobile artillery launcher Monday after consecutive days of erratic mortar fire coming from the Syrian side of the armistice line.

Shelling debated

Military officials and analysts in Israel said they viewed the shelling by the Syrian government forces as unintentional spillover and that Israel had no desire to get involved in the Syria conflict. But some Israelis said that after 40 years of relative stability in the Golan area, the Assad government may be trying to push them into a fight that could galvanize Arab hostility toward Israel and distract attention from its own problems.

Others said Assad was unlikely to want to provoke Israel, afraid of a crushing response that could weaken him militarily. If, for example, an errant Syrian shell hit a school filled with children on the Israeli side, said professor Moshe Maoz at the Hebrew University of Jerusalem, a strong Israeli strike on Syrian government forces would be all but guaranteed.

"Assad knows very well that Israel does not have a sense of humor here and can retaliate very heavily," he said.

Regardless, there is fear in Israel that the situation could escalate.

The United Nations, which monitors an armistice agreement between Israel and Syria in force since the 1973 war, has said it fears that Golan violence could jeopardize the cease-fire.

There was no sign that the violence was abating elsewhere inside Syria. Activist groups said warplanes were dropping bombs in Damascus suburbs and that army snipers had taken up positions in areas where bombs had been dropped. The mayhem surrounding central Damascus made residents in the central part of the capital feel increasingly isolated.

"The inside of the city is like a big prison now," said Alexia Jade, an activist contacted in Damascus. "The checkpoints have increased, and the lines of cars waiting to be searched are getting longer."