After a meeting with President Egils Levits, a joint press conference was held, during which Stoltenberg again said that while NATO supports Ukraine's defense against Russia's unprovoked attack, it will not enter the conflict directly.
"The Ukrainian people and armed forces have inspired the world with their courage, but President Putin's assault continues and the humitarian impact is devastating," said Stoltenberg, noting that 2 million people had so far fled Ukraine.
"Targeting civilians is a war crime and it's totally unacceptable," the NATO Secretary General said.
"Near total isolation on the world stage" plus unprecedented sanctions were part of the heavy price being paid by Russia for its actions, he added.
"The suffering we now see in Ukraine is horriffic. It affects us all. And we have a responsibility to ensure the conflict does not escalate and spread beyond Ukraine. That would be even more dangerous, destructive and even more deadly. The situation could spiral out of control," he said.
"To make sure there is no room for miscalculation in Moscow" NATO had strengthened its eastern flank and had 130 jets on high alert, Stoltenberg said, pledging to "protect and defend every inch of Latvia" and all Allied territory.
"We need to end this conflict, not expand it," Stoltenberg said.
Both men repeated several times the familiar line about NATO being the strongest alliance in history and the determination to defend every inch of NATO territory.
For his part President Levits said: "We are safe, we are protected, we are in solidarity with other NATO member states," and suggested that this would deter Moscow from further aggression.
"Moscow understands the language of strength and NATO is the world's strongest military defensive alliance," Levits said.
He did not repeat his comments from March 5 at the rally for Ukraine when he appeared to hint that a no-fly zone was an option worth considering. On that occasion he had said "We are in favor of all options being considered! Absolutely all!" with regard to requests for a no fly zone made by Ukraine's President Zelensky.