SYRIAN FIGHTER JETS pounded rebel areas across the country yesterday with scores of airstrikes that anti-regime activists called the most widespread bombing in a single day since Syria’s troubles started 19 months ago.

The death toll for what was supposed to be a four-day cease-fire between the regime of President Bashar Assad and rebels seeking his overthrow exceeded 500.

Fighter jets

Activists said more than 80 people were killed nationwide on Monday while videos posted online showed fighter jets screaming over Syrian towns, mushroom clouds rising from neighborhoods and residents searching the remains of damaged and collapsed buildings for bodies.

The airstrikes focused on rebel areas in the northern provinces of Aleppo and Idlib, as well as on restive areas in and around the capital Damascus.

But analysts say that rampant defections and rising rebel capabilities have lessened the regime’s ability to take back and hold rebel areas, making air strikes its most effective way to fight back.

Yesterday was supposed to be the fourth and final day of an internationally sanctioned cease-fire to coincide with the Muslim holiday of Eid al-Adha, one of the holiest periods of the Muslim calendar. But violence marred the truce almost immediately after it was to go into effect on Friday and continued apace through the weekend.

Ban Ki-moon

UN Secretary-General Ban Ki-moon said on Monday he was “deeply disappointed” that the warring parties didn’t respect the cease-fire and called on the divided international community to unite to stop the bloodshed.

As long as the international community remains at odds, the needs, attacks and suffering will only grow.

Envoy Lakhdar Brahimi, who represents the UN and the Arab League and presented the plan, told reporters in Moscow that he’d keep trying to lessen the violence and “put an end to it.”

World powers remain divided on how to stop Syria’s crisis, with the US and many Arab and European nations calling for Assad to step down while Russia, China and Iran continue to back the regime.

Anti-regime activist say more than 35,000 people have been killed since the anti-Assad uprising started in March 2011. The holiday cease-fire was the first international effort in months to try to stop the violence, and it accomplished little.

The Britain-based Syrian Observatory for Human Rights said more than 500 people had been killed during the four-day holiday. It said more than 80 people were killed on Monday and that the number was likely to rise further.

But in a change, Rami Abdul-Rahman, head of the Observatory, said the number of airstrikes spiked on Monday.

Among the hardest hit areas was the northern town of Maaret al-Numan, which rebels seized earlier this month only to face heavy retaliation from the military.

Car bomb

Also yesterday, a car bomb exploded in the Damascus suburb of Jarmana, knocking balconies off of residential buildings and sending firemen rushing to fight the blaze, according to TV footage. The state news agency SANA said 11 people were killed and 67 wounded. The Observatory said five people were killed.

In Turkey, about 150 members of the Syrian opposition met Monday to discuss how to manage rebel-held areas and plan for a post-Assad future.

Abdelbaset Sieda, president of the Syrian National Council, said the Syrian regime was losing its grip on power and that the opposition must be prepared to rebuild the devastated country.

Read: Syria ceasefire in tatters as fighting rages>