Guterres was referring Thursday to the escalating crisis between the US and Iran in the wake of the unraveling nuclear deal with world powers.
The UN chief told reporters "it is absolutely essential to avoid any escalation of the situation", AP reported.
Guterres said he has "no particular insight" into the possibility of a meeting between US President Donald Trump and Iran's President Hassan Rouhani during the annual meeting of world leaders at the UN General Assembly starting Sept. 23, according to Financial Tribune.
But he said any effort to avoid a confrontation "will always be welcome".
Trump has said he is open to sitting down with Rouhani without preconditions to discuss Iran's nuclear program. However, Tehran says the lifting of sanctions is a prerequisite to any talks.