UN Secretary-General Antonio Guterres Sunday said he regrets the Security Council's failure to demand a ceasefire in the Gaza Strip, condemning the divisions that have "paralyzed" the world body.

The body's "authority and credibility were severely undermined" by its delayed response to the conflict, he said two days after a U.S. veto prevented a resolution calling for a Gaza ceasefire.

"I reiterated my appeal for a humanitarian ceasefire to be declared," he told Qatar's Doha Forum. "Regrettably, the Security Council failed to do it," he added. "I can promise, I will not give up."