The decree allows 230 Russian soldiers to enter Nicaragua between July 1 and Dec. 31 to patrol in Pacific waters with the Nicaraguan Army.

President Daniel Ortega has backed Russian President Vladimir Putin in his attack on Ukraine and the decision was expected.

Since 2012, Nicaragua's unicameral Congress has biannually approved the entry of foreign military personnel, including Russians, into the country.

Russian state television had celebrated the decision earlier this month.

The United States expressed its concern.

"We consider this a provocation by the Nicaraguan regime," Brian Nichols, who is in charge of western hemisphere affairs at the State Department, was quoted by DW-TV as saying at the Americas Summit last week.

Nicaragua's Congress also approved the entry of U.S., Mexican, Cuban, Venezuelan and other Central American military personnel, specifying that it is "for humanitarian purposes to carry out joint work with the Nicaraguan Army."