BEIRUT (AP) ― Tens of thousands of defiant Syrian protesters thronged the streets of Homs Tuesday, calling for the execution of President Bashar Assad shortly after his army pulled its tanks back and allowed Arab League monitors in for the first time to the city at the heart of the anti-government uprising.

The pullback was the first sign the regime was complying with the League’s plan to end the 9-month-old crackdown on mostly unarmed and peaceful protesters.

Yet amateur video released by activists showed forces firing on protesters even while the monitors were inside the city. One of the observers walked with an elderly man who pointed with his cane to a fresh pool of blood on the street that he said had been shed by his son, killed a day earlier.

The man, wearing a red-and-white checkered headdress, then called for the monitor to walk ahead to “see the blood of my second son” also killed in the onslaught.

“Where is justice? Where are the Arabs?” the old man shouted in pain.

Syrian tanks had been heavily shelling Homs for days, residents and activists said, killing dozens even after Assad signed on early last week to the Arab League plan, which demands the government remove its security forces and heavy weapons from city streets, start talks with opposition leaders and allow human rights workers and journalists into the country.

But a few hours before the arrival of the monitors, who began work Tuesday to ensure Syria complies with the League’s plan, the army stopped the bombardment and pulled some of its tanks back.

The British-based activist group Syrian Observatory for Human Rights confirmed that government forces fired on protesters while the monitors were inside Homs and said at two people were killed from the fire.

About 60 monitors arrived in Syria Monday night ― the first foreign observers Syria has allowed in since March, when the uprising against Assad’s authoritarian rule began. The League said a team of 12 visited Homs.

After agreeing to the League’s pullback plan on Dec. 19, the regime intensified its crackdown on dissent; government troops killed hundreds in the past week and Syria was condemned internationally for flouting the spirit of the agreement.

On Monday alone, security forces killed at least 42 people, most of them in Homs. Activists said security forces killed at least 16 people Tuesday, including six in Homs.

One group put Tuesday’s toll at 30, including 13 in Homs province. Different groups often give varying tolls. With foreign journalists and human rights groups barred from the country, they are virtually impossible to verify.

Amateur videos show residents of Homs pleading with the visiting monitors for protection.

“We are unarmed people who are dying,” one resident shouts to one observer. Seconds later, shooting is heard from a distance as someone else screams: “We are being slaughtered here.”

Given the intensified crackdown over the past week, the opposition has viewed Syria’s agreement to the Arab League plan as a farce. Some even accuse the organization of 22 states of complicity in the killings. Activists say the regime is trying to buy time and forestall more international condemnation and sanctions.

“The Syrian government will cooperate symbolically enough in order not to completely alienate the Arab League,” said Bilal Saab, a Middle East expert at the Monterey Institute of International Studies in California. “But make no mistake about it, its survival strategy is to keep kicking the can down the road, until domestic and international circumstances change in its favor.”

Opponents of Assad doubt the Arab League can budge the autocratic leader at the head of one of the Middle East’s most repressive regimes. Syria’s top opposition leader, Burhan Ghalioun, called Sunday for the League to bring the U.N. Security Council into the effort. The U.N. says more than 5,000 people have been killed since March in the political violence.

Shortly after the tanks pulled back and stopped shelling, the videos showed tens of thousands flooding into the streets and marching defiantly in a funeral. They carried the open casket overhead with the exposed face of an 80-year-old man with a white beard.

“Listen Bashar: If you fire bullets, grenades or shells at us, we will not be scared,” one person shouted to the crowd through loudspeakers. Many were waving Syria’s independence flag, which predates the 1963 ascendancy of Assad’s Baath party to power.

“The people want to execute Bashar,” chanted a group as they walked side-by-side with monitors through one of Homs’ streets. “Long live the Free Syrian Army,” they chanted, referring to the force of army defectors fighting Assad’s troops.

The amateur video also showed a man picking up the remains of a mortar round and showing it to the observers.

In another exchange, a resident tells a monitor: “You should say what you just told the head of the mission. You said you cannot cross to the other side of the street because of sniper fire.”

The monitor points to the head of the team and says: “He will make a statement.” The resident then repeats his demand, and the monitor, smoking a cigarette, nods in approval.

The Observatory for Human Rights said as the monitors visited Homs, tens of thousands of protesters gathered in some neighborhoods to “reveal the crimes committed by the regime.”

Later, the Observatory said some 70,000 protesters tried to enter the tightly secured Clock Square but were pushed back by security forces that fired tear gas and later live bullets, killing at least two, to prevent them from reaching the city’s largest square. The Local Coordination Committees, another activist group, said security forces were shooting at protesters trying to reach the central square.

Homs, Syria’s third-largest city, has a population of 800,000 and is at the epicenter of the revolt against Assad. It is about 100 miles (160 kilometers) north of the capital, Damascus. Many Syrians refer to it as the “Capital of the Revolution.”

Opposition activist Mohammed Saleh said four days of heavy bombardment in Homs stopped in the morning on Tuesday and tanks were seen pulling out. Another Homs activist said he saw armored vehicles leaving early on a highway leading to the eastern city of Palmyra. He asked that his name not be made public for fear of retribution.

“Today is calm, unlike previous days,” Saleh said. “The shelling went on for days, but yesterday was terrible.”

The Observatory said some army vehicles pulled out of Homs while other relocated in government compounds “where (they) can deploy again within five minutes.”

A local official in Homs told The Associated Press the team of monitors, headed by Sudanese Lt. Gen. Mohamed Ahmed Mustafa al-Dabi, met with Ghassan Abdul-Aal, the governor of Homs province. After the meeting, the monitors headed to several tense districts including Baba Amr and Inshaat, sites of the most intense crackdowns since Friday.

The official later said that most members of the Arab team headed back to Damascus, while three will spend the night in Homs. The official refused to give details about where the observers will stay for security reasons.

In addition to the deaths reported by activist groups Tuesday, Syrian state-run news agency SANA said two roadside bombs targeted a bus carrying employees of a state company in Idlib, killing six and wounding four.

Also Tuesday, a Lebanese-based al-Qaida-linked group, Abdullah Azzam Brigades, claimed that two suicide attacks against Damascus security offices that killed at least 66 Friday were the work of the Syrian regime, and not al-Qaida as Syrian authorities said.

And in Lebanon, security officials said Syrian troops opened fire at a car that crossed illegally into northern Lebanon, killing three Lebanese men. Some Syrians have fled to Lebanon to escape the fighting, and Syria has complained that weapons are smuggled across its borders. It was not immediately clear if the shooting was related to the uprising in Syria.