Donald Trump has said he can override a directive from congress preventing him from recognizing Russian sovereignty over Crimea.

The U.S. president quietly issued a statement on Monday evening, hours after signing a military spending bill, claiming dozens of the bill’s statutes to be unconstitutional intrusions on his powers as commander-in-chief, The Independent reports.

Among the provisions in the $716 billion bill is a ban on spending Department of Defense money on “any activity that recognizes the sovereignty of the Russian Federation over Crimea”, a region in Ukraine annexed by Moscow in 2014 during a period of regional political upheaval.

The bill, titled the John S McCain National Defense Authorization Act for Fiscal Year 2019, does allow for the directive to be waived, but only on condition the secretaries of defense and state provide explanations to relevant senate and house committees.

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However, in a statement published on the White House website, Mr Trump said the provision was an attempt to “dictate the position” of the U.S. in foreign military affairs.

He would treat the directive “consistent with the president’s exclusive constitutional authorities”, which Mr Trump claimed included the authority “to determine the terms upon which recognition is given to foreign sovereigns”.

During the signing ceremony at Fort Drum, New York state, on Monday, Mr Trump pointedly failed to mention John McCain, the Republican senator whom congress named the bill in honour of.

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It appeared to be another slight in the long-running feud between the pair, which was first sparked in 2016 when Mr Trump said the military veteran was “not a war hero” because he was captured during the Vietnam war.

Mr McCain, who is battling brain cancer, last month branded Mr Trump’s meeting with Vladimir Putin in Helsinki as “one of the most disgraceful performances by an American president in memory.”