NEW YORK (Reuters) - Moody's Investors Service on Thursday said that any future changes to the U.S. sovereign credit rating will turn on the expected debt trajectory, with more budget measures needed to shrink key debt ratios.

If the United States does not see high growth rates, the debt-to-GDP ratio could suffer, Moody's said in a statement.

"Therefore, further fiscal policy actions in coming months would be needed to ensure a decline in the debt ratios," the statement added.

"Any rating action in coming months will be predicated on the expected debt trajectory, which in turn will result from fiscal policy and the expected path of economic growth."

Moody's rates the United States Aaa with a negative outlook. Fitch rates the country AAA with a negative outlook. Standard and Poor's rates the United States AA-plus, also with a negative outlook.

(Reporting By Luciana Lopez and Daniel Bases; Editing by Chizu Nomiyama)