UN Secretary General Ban Ki-moon said Tuesday that Islamists in Syria and Iraq pose a threat to world security but he stopped short of endorsing US-Arab airstrikes in Syria.
"It is undeniable and the subject of broad international consensus that these groups pose an immediate threat to international peace and security," Ban told a news conference at UN headquarters in New York.
He spoke a few hours after the United States and its Arab allies unleashed strikes on jihadists in Syria, opening a new front in the battle against the Islamic State group.
The UN chief noted that the airstrikes were not carried out in response to a Syrian request, as is the case for Iraq, but that Damascus was informed of the operation.
"All measures must be fully in line with the Charter of the United Nations," Ban stressed, citing the need to protect civilians and limit casualties in line with international humanitarian law.
US President Barack Obama is due to chair a Security Council meeting on Wednesday on choking off the flow of foreign fighters to Iraq and Syria, by asking governments to adopt laws making it a serious crime to join jihad.
Ban urged world leaders to "come together decisively in support of efforts to confront these groups".