Ukrainian President Volodymyr Zelenskyy on Monday called for increased pressure on Russia following the Palm Sunday missile attack on Sumy. Russia claims the deadly strike that killed and wounded scores, including children, had targeted a gathering of Ukrainian troops. Zelenskyy welcomed the international condemnation of the attack and called for more pressure on Russia to end the violence. "If there is not enough pressure on Russia, they will continue to do what they are used to - continue to fight," he said. The president also mentioned that his office was "planning meetings" with international allies regarding a military contingent in Ukraine. This security mission was aimed at maintaining peace after the end of the war, he said. "Today, all day long, work continues in Sumy after yesterday's Russian ballistic missile strike to clear the rubble. Almost 40 wounded (people) are still in hospitals, including children, 11 of whom are in a serious condition, and doctors are trying to do everything they can to help save lives. All manifestations of support are very important now - every leader, every country, all diplomatic representatives who have spoken out - we see and hear them all." "Russian state propagandists are preparing their audience for the fact that negotiations and diplomacy will not work. And there is only one reason for this: they are not afraid in Moscow right now. And if there is not enough pressure on Russia, they will continue to do what they are used to - continue to fight. It has become a Russian state habit to fight against its neighbors, to promote hatred and destroy lives. We all want this to stop. Peace is needed and it must be lasting."