Syrian tank fire killed at least three people in the city of Homs early on Friday as security forces pursued a violent crackdown on protesters despite a government agreement with the Arab League to stop shooting and talk to its opponents.

The latest deaths followed a bloody day in Homs, where activists said at least 22 people were killed as tanks shelled the Bab Amro district and troops and snipers fired elsewhere in the city, a hotbed of protests and an emerging insurgency.

One witness, who asked not to be named, said he had seen dozens of bodies of civilian men with bullet wounds at the city's National Hospital, controlled by the security forces.

There was no independent confirmation of the killings.

Tough media curbs have made it hard to verify events in Syria since protests against President Bashar al-Assad began in March, inspired by other revolts against Arab autocrats.

The state news agency SANA headlined its report on Homs: 'Homs residents condemn the armed terrorists' acts and stress their ties to foreign agendas targeting Syria's stability.'

It quoted a woman named Ikhlas Ashour as saying gunmen had hijacked the shared taxi she had taken in Homs and after a short drive forced the passengers out, robbed them of their money and identity cards and killed all the men.

'It was an indescribably ugly scene, I felt like I was living a nightmare,' she was quoted as saying.

Another resident, Ghayath Darwish, told SANA he and his father had been in a shared taxi in the city's Jab Abbas district when armed men intercepted it and killed some male passengers at random, 'dragging away their corpses.'

SANA also said that 13 soldiers killed by 'armed gangs' in Homs, the city of Hama and the northwestern province of Idlib were returned to their families for burial on Thursday.

The violence in Homs, where tanks were bombarding for the second straight day, illustrates how difficult it will be to implement the Arab League plan in a country locked in a deadly struggle between Assad and foes of his 11-year rule.

Fears that the unrest is taking a sectarian turn have mounted this week, amid reports of killings of members of Assad's minority Alawite community and counter-killings of Sunni Muslims, who form a majority of Syria's 20 million people.

Assad's opponents say the only way to restore peace in Syria is for the president to step down immediately.

The security forces do not appear to have changed course despite Syria's acceptance on Wednesday of the Arab proposals for an army withdrawal from cities, the release of political prisoners and talks with the opposition.

'We have already seen the regime's bloody response to the Arab initiative today in the form of intensified shelling on Homs,' Ahmad Ramadan, spokesman for the opposition Syrian National Council, said on Thursday.

'If its forces keep firing on protesters, Arab states may be forced to take a more decisive position and support the case for international protection for civilians.'

The renewed tank fire in Homs occurred hours before weekly Muslim prayers, often a focal point for protests.

'The wounded in Bab Amro are dying where they fall. The bombardment is so heavy that no one can get to them,' Samer, an activist who had fled the district, told Reuters by phone.

Activists also said dozens of people had been arrested in the early hours in the northern Damascus suburbs of Douma and Harasta. They said soldiers were entering Mouadhamiyeh, a suburb to the west of the capital.

The United Nations says more than 3,000 people have been killed since the uprising against 41 years of Assad family rule began in March. The authorities accuse Islamist militants and foreign-backed armed gangs of killing 1,100 soldiers and police.

Western sanctions and growing criticism from Turkey and Arab neighbours have raised pressure on Syria to end the bloodshed.-Reuters