In memos addressed to acting Pentagon chief Patrick Shanahan and Navy secretary Richard Spencer, General Robert Neller wrote that he had been forced to cancel or reduce exercises in five countries.

Marines will miss exercises in Indonesia, Scotland and Mongolia, and their participation in joint exercises in Australia and South Korea will be reduced, Neller said in the documents dated March 18 and 19.

A Marine Corps spokesman confirmed the validity of the documents published by the LA Times.

Neller said Trump's emergency declaration to secure $6.7 billion from the Pentagon's 2019 budget for his wall meant the corps could not afford to rebuild hurricane-hit bases in North Carolina and Georgia.

"The hurricane season is only three months away... and we have Marines, Sailors, and civilians working in compromised structures," Neller wrote.

"While (financial year 2019) was supposed to be a 'good year' given an 'on-time' enacted budget and topline, those positive attributes are now overcome by the negative factors... imposing unacceptable risk to Marine Corps combat readiness and solvency," he added.

Shanahan has not yet released the funds claimed by the president.

"Monetarily, recovery for those areas affected by the hurricanes is by far the most significant budgetary pressure listed in the memo," said Marines spokesman Captain Joseph Butterfield.