Rights groups say Syrian forces have killed at least 41 civilians, including two young girls, in recent efforts to crush pro-democracy protests in central and southern areas of the country.

Government troops backed by tanks continued lethal attacks for a fourth straight day Wednesday on towns around the central city of Homs, including al-Rastan and Talbiseh.

The majority of the killings, including Tuesday's fatal shooting of a 4-year-old girl, took place in al-Rastan. Syrian forces also shelled the southern town of Hirak Tuesday, killing at least eight people, including an 11-year-old girl. Dozens of men over the age of 18 were arrested in Hirak as troops stormed houses and snipers deployed in the streets.

Rights groups say at least 25 children are among the more than 1,000 people killed in the uprising against President Bashar al-Assad. They say his security forces have arrested 10,000 more in a campaign to crush the unprecedented protests.

Witness reports in Syria, as well as official accounts, are difficult to independently verify because the government barred most international journalists from the country soon after the unrest began.

Meanwhile, Syrian opposition leaders meeting in Turkey have rejected their government's offer of a general amnesty and say they will continue to push for a regime change.

More than 300 dissidents attended a conference in the Turkish town of Antalya Wednesday – the first official meeting of activists and opposition figures in exile since demonstrations erupted more than two months ago in the southern city of Daraa.

The Syrian government freed hundreds of political prisoners Wednesday, a day after Mr. Assad announced the amnesty. The releases are an apparent bid to appease activists calling for his resignation.

The United States and France both said the amnesty would not be enough. U.S. State Department spokesman Mark Toner said the president's effort fell short and that all political prisoners need to be freed. In Paris, French Foreign Minister Alain Juppe said Syrian authorities must be “much more ambitious, much bolder than a simple amnesty.”

Also Wednesday, President Assad announced the formation of a committee to map out a national dialogue with the opposition. State-run media quote him as saying the talks will address issues related to Syria's social, economic and political future.

In another development, Human Rights Watch said it has reports of recent killings and torture by Syrian troops that may qualify as crimes against humanity. The New York-based group released a report Wednesday based on more than 50 interviews with victims and witnesses of the violence.

The report centers on the southern city of Daraa, where Syrian forces allegedly carried out some of the worst violence against civilians since anti-government protests began in March.

The rights group says witnesses told of beatings, torture using electroshock devices, and the detention of people seeking medical care. It called on the Syrian government to take steps immediately to halt the use of excessive force.

Syrian opposition activists have been protesting almost daily since March for democratic reforms and an end to Mr. Assad's 11-year autocratic rule.