Rights activists say Syrian army defectors have killed at least 27 soldiers and security force members, while a new report accuses military officials of authorizing the halting of protests by “any means necessary.”

The London-based Syrian Observatory for Human Rights said the deaths occurred during multiple clashes early Thursday in the southern province of Daraa.

Syria's anti-government uprising has turned increasingly violent in recent months, with defecting soldiers fighting back against the army and once-peaceful protesters taking up arms to protect themselves.

Rights activists said violence across Syria on Wednesday killed at least 25 people, including eight Syrian troops who died in a retaliatory attack by suspected army defectors.

Meanwhile, Human Rights Watch released a report Thursday saying Syrian army defectors have named 74 commanders and officials they say are responsible for attacks on unarmed protesters.

The group says that based on interviews with the former soldiers and intelligence agency defectors, there is “no doubt” that government security forces have committed widespread abuses. It says the government had a policy targeting civilians that resulted in killings, arbitrary detentions and torture, and that the abuses constitute crimes against humanity.

The United Nations says more than 5,000 people have died since March, when the unrest first began. But Syria's U.N. ambassador has rejected that figure as “incredible.”

U.N. Secretary-General Ban Ki-moon told reporters in New York on Wednesday that “in the name of humanity” it is time for the international community to act. He said the “status quo in Syria cannot go on.”

In Washington, a congressional committee on foreign affairs examined U.S. policy toward Syria. Some members questioned whether the Obama administration should continue to advocate for a peaceful resolution in Syria in the face of widespread violence. Others echoed calls by President Barack Obama for Syrian President Bashar al-Assad to step down and end the killing, detention and torture of demonstrators.