NEW YORK (TheStreet) -- A top Russian economic official says his country is likely to continue decreasing the share of its portfolio that consists of U.S. debt, according to a published media report.

"The share of our portfolio in U.S. instruments has gone down and probably will go down further," said Arkady Dvorkovich, chief economic aide to Russian President Dmitry Medvedev, according to a report on

The Wall Street Journal's

Web site.

Dvorkovich made the comments on the sidelines of the St. Petersburg International Economic Forum, the report said.

Foreign countries' interest in purchasing U.S. debt has become an important concern as the U.S. government is running large deficits and must finance them by selling Treasuries. A weakening appetite for Treasuries would drive up the cost of Washington's borrowing.

One recent source of Treasury demand, the

Federal Reserve's

QE2 program, is scheduled to come to an end later this month.

Russian holdings of U.S. Treasuries fell to $125.4 billion in April 2011 from $176.3 billion in October 2010, the


report noted, citing Treasury Department data.

According to the report, Dvorkovich was asked whether U.S. debt was as solid an investment now as it was a decade ago.

He replied: "On an absolute basis, yes. On a relative basis, compared to other investments, of course not ... When we take decisions and compare, we're not thinking in absolute terms."

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This article was written by a staff member of TheStreet.