Finland has accused Russia of trying to create a migration crisis following the Nordic nation's entry into NATO this year.
Recep Tayyip Erdogan had accused Stockholm of being too soft on Kurdish militants and other groups he considers to be security threats.
The U.S. president appeared to have a short fuse after trying to end a NATO summit presser.
NATO opened its summit Tuesday with fresh momentum after Turkey withdrew its objections to Sweden joining the alliance.
Ahead of the NATO summit in Lithuania, the president said that Russia's war must end before the defense alliance can invite Kyiv to join.
Most NATO countries had been keen to name a woman to the top post.
NATO chief Jens Stoltenberg has defiantly declared that Ukraine's “rightful place” is in the military alliance and pledged more support.
The move is a strategic and political blow to Putin, who has long complained about NATO’s expansion toward Russia and partly used that as a justification for the invasion.
U.S. Secretary of State Antony Blinken will announce substantial U.S. aid for Ukraine’s energy grid.
“We have no indication that this was the result of a deliberate attack,” said NATO Secretary-General Jens Stoltenberg.