By Stephanie Nebehay
GENEVA (Reuters) - Killings, crimes and other abuses by rebels, including foreign fighters invoking jihad, or holy war, have increased in northern Syria, U.N. human rights investigators said on Monday.
"Across northern Syria, there has been an upsurge in crimes and abuses committed by extremist anti-government armed groups along with an influx of rebel foreign fighters," Paulo Pinheiro, head of the inquiry, told the U.N. Human Rights Council.
"Entire brigades are now made up from fighters who have crossed into Syria, with Al Muhajireen being one of the most active," he said.
The investigators have previously said foreign fighters from more than 10 countries, including Afghanistan and Russia's Chechnya region, as well as al Qaeda-linked al Nusra forces are backing Syrian rebels. The Lebanese Hezbollah is fighting alongside government forces.
"Now it is probably more. The point is that these extreme elements have their own agenda and certainly not a democratic agenda that they are seeking to impose," commission member Vitit Muntarbhorn said. "That is a major worry from our side of the fence."
Pinheiro, reporting on suspected war crimes since July 15, also said President Bashar al-Assad's government had continued a relentless campaign of air bombardment and artillery shelling across the country.
An incendiary bomb dropped from a government warplane on a school in the Aleppo countryside on August 26 killed at least eight students, and 50 more suffered horrific burns over up to 80 percent of their bodies, he said, citing survivor accounts.
(Reporting by Stephanie Nebehay; Editing by Angus MacSwan)