Rebels are begging the West to impose a no-fly zone over Syria as they shot down a Syrian Air Force plane with anti-aircraft weapons that have helped kept their spirits high in the face of another wave of executions by the Syrian army.

An opposition source working with rebels in the area told Reuters the rebels used anti-aircraft guns to down the jet.

"It was a Mig-21 brought down by a 14.5 anti-aircraft gun, the biggest in the rebel arsenal. The plane was flying too low and was within range. We have no information whether the pilot survived," the source said.

Defected Brigadier General Ibrahim al-Jabawi told the Egyptian Al Arabiya channel Monday that Iranian military advisors led Syria’s feared Shabiha unit when they stored Homs. He said that 10 people were publicly executed, and approximately 350 others were “detained.” Other sources confirmed the account.

Another execution of 10 people was also reported in Damascus, but one video also has shown rebels committing atrocities such as throwing captured Syrian soldiers off rooftops.

Battles continued to rage in the commercial center of Aleppo and in the capital of Damascus as the world continues to refrain from direct intervention to stop the slaughter that has claimed nearly 20,000 lives. Approximately 150,000 Syrians have fled to Jordan, Lebanon and Turkey.

“There is massive destruction as well as many people killed and injured,” an activist told CNN via Skype. “We call for help to break the siege around the city. There is no running water or electricity. There is lack of food and baby formula. The only automated bakery was shelled so we have lack of bread as well."

No end to the civil war appears in sight, but U.S. Secretary of State Hillary Clinton reasoned that that civil war must be stopped in a way that does not result in more brutality.

"There is a very clear understanding about the need to end this conflict quickly, but not doing it in a way that produces even more deaths, injuries and destruction," Clinton said after speaking with Turkish  Foreign Minister Ahmet Davutoglu.

The United Nations, which has failed to reach any effective agreement with Syrian President Bashar Assad, still thinks it has a part to play.

United Nations humanitarian chief Valerie Amos is going to Syria and Lebanon for a three-day visit starting Tuesday to discuss ways of increasing emergency aid to civilians caught up in the conflict, a U.N. statement said on Monday.

"The three-day visit aims to draw attention to the deteriorating humanitarian situation in Syria and the impact of the conflict on people either remaining in Syria and who have fled to other countries, including Lebanon," it said.