(CNN) -- In the wake of the attack on Malaysia Airlines Flight 17, "every country, including Russia," must determine whether it is "together with the terrorists or together with the civilized world," Ukrainian President Petro Poroshenko said Monday.
In an exclusive interview with CNN's Christiane Amanpour, Poroshenko said, "Every country and every person, and every leader should find out their own place."
"We know exactly" where a missile was shot that hit the plane Thursday, killing all 298 people aboard, and where the flight crashed, he said. "And all this territory is firmly controlled by Russian-supported terrorists."
Ukraine has "a lot of evidence that these people are supported by Russia, trained by Russia, armed by Russia," he added. "And most of them and their leaders are Russian citizens. That is for sure."
Those armed in eastern Ukraine should not be referred to as "separatists," he insisted. "There are no separatists there. They are terrorists."
The United States should declared them terrorists, he said. Such a designation would trigger a "new legal framework for those who support it" and cooperate "with these terrorists."
Ukraine has suffered "three major international crimes," Poroshenko said.
There is what he called "the terrorist act" on Flight 17 -- which he compared to 9/11 and the 1988 Lockerbie, Scotland, bombing. And the way the bodies have been treated, with their personal belongings taken, is "barbarian style," he said. The third crime is that "terrorists" have tried to destroy evidence, he said.
But the crime scene "is impossible to destroy," Poroshenko said.
"All the shrapnel is dispersed on the territory of about 20 square kilometers (about 8 square miles). This crime, the international crime, is impossible to destroy."
Poroshenko also denied suggestions by Russia that a Ukrainian jet may have downed the plane. "This is an irresponsible and false statement," he insisted.
Moscow has strongly denied involvement in the downing of the jetliner.
Pro-Russian rebels have also denied responsibility.