The G20 meeting of foreign ministers of major economies will begin on Thursday in Johannesburg, South Africa.
Ms Baerbock flew to Damascus from Cyprus on Friday morning.
“But if the Zionist regime takes retaliatory action, our response will be even tougher,” the minister said, referring to possible Israeli retaliation.
Mr Guterres, whose second term ends in 2026, has supported a female successor.
German politicians are outraged after a CNN report detailed an alleged Russian plot to assassinate Armin Papperger, the head of German arms maker Rheinmetall.
Israeli forces have been waging an intense military offensive in the Gaza Strip for seven months.
Ms Baerbock was scheduled to attend the meeting directly after returning from a short visit to Kiev on Tuesday.
This is Ms Baerbock’s seventh trip to Israel since the attack on Israel by the Palestinian militant organisation Hamas and other groups on October 7.
Two generals seized power in a military coup in 2021 but later fell out over internationally backed plans for Sudan’s transition to civilian rule.
At the moment, NATO itself is not officially providing any lethal aid to Ukraine’s defensive war against Russia’s invasion of its territory.
