Hundreds of thousands of people took to the streets after Friday prayers to voice their opposition to Syrian President Basher al-Assad’s Ba’ath party dictatorship and to reject his phoney “national dialogue” conference that started yesterday in Damascus.

Demonstrations took place in Homs, Deir al-Zour, and in other towns and some Damascus suburbs, but by far the largest protests were in Hama, Syria’s fourth largest city.

The regime again responded with tear gas, mass arrests, gunfire and imposed a curfew on the southern town of Inkhil. It is believed that at least 13 people were killed in the protests, including three in Maarrat an-Numan, a northern town near Jisr al-Shugour that has been the scene of a major military intervention, three in Homs, three in Harasta, a suburb of Damascus, and two in Midan, central Damascus.

In Hama, where there was no military presence, there were no reports of violence. Hama has become a focal point for opposition to the government, where protests have grown daily. Last month, the government withdrew its troops after 73 people were killed on June 3 in order to assuage tensions in a city synonymous with the brutal crackdown by Assad’s father, Hafiz al-Assad, nearly 30 years ago that killed an estimated 20,000 oppositionists led by the Muslim Brotherhood.

The government responded to the growing protests, said to have reached 150,000 people a week ago, by sacking the recently appointed governor. His replacement is believed to be a former head of political security and to have played a role in the 1982 events.

The government also sent security forces back into the city on Monday, where they took up positions near the headquarters of the ruling Ba’ath party, the police headquarters and a state security compound. On Tuesday, they opened fire on demonstrators, killing 22 people, wounding 40 and arrested dozens, if not hundreds (reports vary), prompting hundreds to flee the city. On Wednesday, it was reported that parts of the city were without water and electricity. The military has remained on the outskirts of Hama, preventing people from nearby towns and villages from joining the rallies. Some tanks apparently withdrew over the weekend.

In a new development, there were strikes in Hama, Homs and towns in Idlib province to the north.

The growing protests underscore the scale of opposition to the Assad regime and the government’s inability to end it with brute force and vague promises of political reform.

At the behest of regional leaders, who fear that instability in Syria will destabilise political relations in the entire region, Assad has set up a “national dialogue committee” to meet for the first time yesterday and today, to include the ruling Ba’ath Party, “oppositionists” and “independents”.

According to the state media, the meeting will discuss amendments to the constitution, including Article 8 that gives the Ba’ath Party a monopoly of political power as the “leader of state and society”, and new laws on political parties, elections, local administration and the press. Al Watan, the privately owned Damascus-based newspaper, reported that the parliamentary elections scheduled for August are to be postponed pending the reforms.

Most of the so-called “oppositionists”, former supporters or long discredited dissidents, have stayed away, well aware that the angry demonstrators will have no dealings with either the “national dialogue” or its participants as long as the crackdown continues.

Mohammed al-Abdullah, a spokesman for the Local Co-ordination Committees, which claims to represent many protesters, told Al Jazeera, “Dialogue with this regime is out of the question as we cannot talk to murderers. This is being declared by the rebels in the street. The city of Hama is being massacred and besieged, the Syrian people are being tortured, and therefore talk of any dialogue with the regime is a disgrace to the blood of the martyrs.”

While some of Assad’s allies, Ankara and Riyadh in particular, have become more openly critical of Damascus, Washington and Paris now appear to have shifted their position significantly to come out more openly in favour of regime change. Syria, which borders Israel, Lebanon, Iraq, Turkey and Jordan, has a wider regional influence because of its support for Hezbollah in Lebanon and Hamas in Gaza and its alliance with Iran, which plays a key role in Iraq.

The imperialist powers are keen to use the crisis facing the regime to target Syria’s main ally, Iran, and detach Damascus from Tehran. It follows the appointment after five months of bitter political wrangling, of a government backed by Hezbollah, Iran and Syria’s allies, at the expense of the pro-Western faction of Saad Hariri. While they had originally believed that Assad would be able to stem the protests and that it was in their best interests that he should be given the time to do so, they now calculate that the regime is tottering and they should intervene to move events forward in their own interests.

US State Department spokesperson Victoria Nuland said that the US was “very concerned” about continuing and spreading violence that is taking Syria “in the wrong direction” and urged the government to “immediately halt its intimidation and arrest campaign” and to proceed with the political dialogue President Assad had promised.

On Thursday, Robert Ford and Eric Chevallier, the US and French ambassadors to Syria, took the unprecedented step of going to Hama to show their support for the opposition to Assad, staying over Friday, without seeking permission from the authorities in Damascus.

The Syrian government was furious, with the interior ministry calling the visit an act of incitement. State media reported, “The ministry wondered at the US ambassador’s arrival in Hama contrary to the diplomatic norms and despite the roadblocks set up by the saboteurs to prevent citizens from reaching their jobs.” It said that Ford had met “a number of the saboteurs and incited them to more violence and protest and to refuse dialogue”.

The foreign ministry was quoted as saying, “The presence of the US ambassador in Hama, without prior permission from the Foreign Ministry...is a clear evidence of the United States’ involvement in current events in Syria and its attempt to incite an escalation in the situation, which disturbs Syria’s security and stability.”

State television said that the ambassador, “under the cover of visiting some hospitals”, had met other people in an attempt to encourage further violence and instability, to sabotage national dialogue, and to deepen discord and sedition among the Syrian people “who strongly reject and condemn such foreign instigation”.

A senior US official, speaking on condition of anonymity, was quoted by AFP as saying that Ford had visited the city to “make contact” with opposition leaders.

Nuland said that the embassy had informed the Syrian government of a diplomatic visit to the city, although it had not specified that Ford himself would be going. She said, “The fundamental intention was to make absolutely clear with his physical presence that we stand with those Syrians who are expressing their right to speak for change.”

The State Department has also accused Damascus’ embassy in Washington of spying on US demonstrations against the Syrian repression of the protest movement.

On Wednesday, Amnesty International (AI), the London-based human rights organisation, said that Syria’s a “devastating security operation” in Talkalakh near the border with Lebanon on May 14 may have constituted a crime against humanity. It documented instances of arbitrary detentions, torture, abuse and at least nine deaths in custody that it considered were crimes against humanity “as they appear to be part of a widespread as well as systematic, attack against the civilian population”. AI urged the UN to refer Syria to the International Criminal Court.