German Chancellor Angela Merkel said on Thursday it was a scandal that the United Nations Security Council did not pass a resolution condemning a suspected chemical attack in Syria this week which killed at least 70 people.

"It was a barbaric attack that must be cleared up. The use of chemical weapons is a war crime," Merkel told a news conference in eastern Germany, adding there were some indications it was carried out by President Bashar al-Assad's forces.

"It is a scandal that no U.N. Security Council resolution materialised and those who opposed it must consider what responsibility they bear," she said. She declined to interpret U.S. President Donald Trump's comments that the attack went "beyond a red line".