Nearly 50 supporters of Ukraine assembled Friday evening under that nation's flag on the Benjamin Franklin Parkway to plead for action in response to the downing of Malaysia Airlines Flight 17.
Evidence indicated that the passenger jet was shot down Thursday afternoon by a surface-to-air missile fired from an area controlled by Russian-backed separatists in eastern Ukraine, President Obama said earlier in the day at the White House.
All 298 people on board were killed.
"We are here as the Ukrainian community to mourn the victims" of the missile attack, said Mary Kalyna, who helped organized the vigil and protest at 17th and the Parkway.
Kalyna demanded "a full, thorough, impartial investigation, and that those who are responsible be held accountable and brought to justice."
Most of the speakers expressed anger at Russian president Vladimir Putin.
"We are gathered here for 300 who were murdered," said Ulana Mazurkevich, president of Ukrainian Human Rights.
"One man is responsible. We know who that man is. That man is Putin," she said.
"He is dangerous and something more serious needs to be done," said Iryna Halaway, 34, who was born in Ukraine and now lives in the Art Museum section of Philadelphia.
Olesia Malskaya, 41, relocated to Philadelphia from Ukraine a month ago because her husband, an American investment banker, could no longer do business there.
Her 4-year-old son, Sean McCallum, held up a sign that said "I could've been on this plane."