The FINANCIAL -- President Petro Poroshenko is due to testify at ousted predecessor Viktor Yanukovych's treason trial as Ukraine marks the anniversary of the bloodiest day of the Euromaidan protests that pushed the Moscow-friendly leader from power.
The annual commemorations honor protesters, known as the "Heavenly Hundred," who were killed in clashes with security forces in Kyiv on February 20, 2014.
Poroshenko has confirmed that he will take the stand in the in-absentia trial of Yanukovych, who stepped down in the face of the protests and fled to Russia four years ago, according to RFE/RL.
"Evil must be punished. That is why, for the first time in Ukrainian history, I decided to take part in the trial," Poroshenko said on February 18.
Commemorative events planned for February 20 included a solemn ceremony with participants hanging paper angels on trees lining Kyiv's Institutska Street, where some of the protesters were killed, and a rally in the eastern city of Kharkiv honoring the Heavenly Hundred.
The Euromaidan movement began in November 2013, when protesters gathered in central Kyiv after pro-Russian President Viktor Yanukovych announced he was postponing plans to sign an Association Agreement with the European Union and would seek closer economic ties with Russia.
Ukrainian prosecutors say 104 people were killed and 2,500 injured in the protests that centered on Kyiv's Maidan Nezalezhnosti, or Independence Square.
Shunning a Western-backed and Russian-backed deal with the opposition to end the standoff, Yanukovych abandoned power and fled Kyiv on February 21, 2014. The former president, who took refuge in Russia, denies ordering police to fire on protesters and claims the violence was a "planned operation" to overthrow his government.
Moscow responded to his downfall by seizing control of Ukraine's Crimean Peninsula in March 2014 and fomenting separatism across much of the country -- one of the causes of a war that has killed more than 10,300 people in eastern Ukraine since April 2014 and displaced more than 1.6 million Ukrainians.
In a statement marking the February 20 events, U.S. State Department spokeswoman Heather Nauert said that "the United States will continue to stand by Ukraine as it faces ongoing Russian aggression."
Nauert added that although Ukraine had made progress in the last four years, "there is still more work needed to fulfill the promise of the Maidan and unlock Ukraine's potential."
"The United States calls on Ukraine's leaders to redouble their efforts to implement the deep, comprehensive, and timely reforms that are necessary to build the stable, democratic, prosperous, and free country Ukrainians deserve," Nauert said.
Deputy Secretary of State John Sullivan is to meet with Poroshenko, Prime Minister Volodymyr Hroysman, and Foreign Minister Pavlo Klimkin during a visit to Kyiv on February 21.
Sullivan "will stress the importance of Ukraine expeditiously implementing credible economic and anti-corruption reforms and will underscore U.S. support for Ukraine’s sovereignty and territorial integrity," the State Department said.