"I think the European Union has the right and the duty to stand by the people of Ukraine in this very difficult moment," he said in a statement.
The Ukrainian government in November suspended a bid to sign free trade and association agreements with the EU. The government said its decision was based on the need to protect its economic ties to Russia.
The European Union deal for Ukraine could help the former Soviet republic emerge from economic recession. The EU had praised Ukraine for legislative reforms that were in line with European standards, though its justice system was viewed as politically tinged.
Protesters last weekend called on the Ukrainian president to resign.
"When we see in the cold streets of Kiev, men and women with the European flag, fighting for that European flag, it is because they are also fighting for Ukraine and for their future," Barroso said.