UNITED NATIONS (Reuters) - As the fighting in Syria gets worse, forces loyal to Syrian President Bashar al-Assad and rebels determined to oust him are committing an increasing number of violations of international humanitarian law, the EU humanitarian chief said on Tuesday.
"This is an asymmetrical war, and there is a degree of expansion of violation of international humanitarian law on both sides that seems to be escalating," Kristalina Georgieva, the European Union's commissioner for international cooperation, humanitarian aid and crisis response, told reporters.
"This is why it's so important to say in the simplest possible way: 'No, you cannot do that, or if you do it, there will be consequences,'" she said after meeting with Anthony Lake, head of the U.N. children's fund UNICEF.
The Syrian government and allied militia have been accused by the United Nations and Western governments of numerous large-scale massacres, though the rebels are also facing allegations of mass killings.
Amateur video posted on You Tube on Monday showed images of 20 dead Syrian soldiers, blindfolded and handcuffed, after they were apparently executed in the northern city of Aleppo.
Georgieva said that many of the rebels were likely unaware that they, like the government forces, were obligated to comply with international humanitarian law and the Geneva Conventions. But ignorance of legal obligations would be no excuse when the war was over, she said.
UNICEF's Lake said that rebels and government forces alike should be held accountable for any war crimes they commit during the conflict.
"There must be no impunity for anyone on either side," Lake said.
U.N. human rights chief Navi Pillay said on Monday that justice would eventually catch up with anyone on either side of the Syrian conflict who was guilty of war crimes.
The United Nations has said that over 20,000 people have been killed in the 18-month conflict in Syria. Syrian opposition groups say that more than 27,000 have died.
The United Nations has said that the better-armed government forces and their allies have killed more people than the rebels, though neither side has clean hands in a conflict that is now widely seen as a full-scale civil war.
Both Georgieva and Lake appealed for humanitarian pauses in the fighting to allow humanitarian access to conflict zones and evacuation of the most vulnerable elements of the Syrian population - children, the elderly and women - who have been bearing the brunt of the attacks on civilian areas.
(Editing by David Brunnstrom)