Visiting NATO Secretary General Anders Fogh Rasmussen on Friday called on Russia "to step back from the brink," local media reported, Xinhua reported.
Addressing at Tallinn University during his second day of the visit, the NATO head said he had just two messages to deliver to the audience about his appearance in the country, the first one to Russia, whose actions in Ukraine he called "illegitimate and illegal" violations of international law.
"(Russia should) step back from the brink," he said, adding "Rejoin the international system and fulfill your international commitments. Because these are critical to your own security and the entire world."
Rasmussen said his second message was to the people of Estonia and its Baltic neighbors who have seen ground and air forces stationed in their countries or reinforced in the last two months.
"NATO stands with you. You may be on NATO's border geographically, but you are right at the core of our alliance politically. NATO will do what it takes to defend you and all the allies; to do what it takes to defend our populations and societies against any threat," said Rasmussen.
"NATO's commitment to collective defense is rock solid. And it will remain rock solid," he said.
Rasmussen left Tallinn University for Amari air base near Tallinn where some 150 U.S. soldiers and 100 UK soldiers arrived last week for joint NATO Baltic military exercises, rounding up his two day visit to Estonia and flying back to NATO headquarters in Brussels Friday evening.