(Adds quotes, U.S. delegation visit)
WASHINGTON, Feb 24 (Reuters) - U.S. Senator John McCain said on Monday the United States, as well as the International Monetary Fund and European Union, must be ready to provide additional assistance to Ukraine.
"Now more than ever, the Ukrainian people need the continued support of their friends," the Arizona Republican, one of his party's leading voices on foreign relations, said in a statement.
McCain also said it was "deeply concerning" that some Ukrainians and Russians seemed to be questioning Ukraine's sovereignty and territorial integrity. McCain and a Democratic senator, Chris Murphy of Connecticut, traveled to Kiev in December and addressed anti-government protesters.
McCain and other U.S. lawmakers last week discussed legislation to impose sanctions on Ukraine in response to violence surrounding protests against the government of Russian-backed President Viktor Yanukovich.
Congressional aides said that discussion is now shifting to the topic of possible aid.
Ukraine has appealed for urgent international help to keep its economy from "heading into the abyss" now that Yanukovich has been ousted.
A U.S. delegation led by Deputy Secretary of State William Burns to Ukraine this week will include officials from the Treasury Department and the National Economic Council.
Russia has pledged $15 billion in economic aid to the former Soviet bloc nation. (Reporting by Patricia Zengerle; Editing by Doina Chiacu)