"I think that what has happened is particularly serious, not only because of the number of victims that it caused, but because of the indications that exist that this was triggered," Guterres told the reporters.
His remarks came a day after at least 12 people, including children, were killed and thousands wounded when Hezbollah members' pagers were detonated across Lebanon.
The Lebanese group Hezbollah confirmed that at least two members were killed and many injured in the explosions and held Israel fully responsible for the incident.
"Because obviously the logic of making all these devices explode is to do it as a preemptive strike before a major military operation. So as important as the event in itself is the indication that this event confirms that there is a serious risk of a dramatic escalation in Lebanon, and everything must be done to avoid that escalation," Guterres said.
The pager blasts came amid mounting border escalation between Israel and Hezbollah, which have been engaged in cross-border warfare since the start of Tel Aviv’s deadly war on the Gaza Strip, which has killed over 41,200 people, mostly women and children, following a Hamas attack Oct. 7 last year.