Donald Trump has been mocked for colouring in the American flag incorrectly during a visit to a children’s hospital in Ohio.

The US president was photographed adding a blue stripe to an outline of the star-spangled banner, rather than correctly filling in the 13 alternating red and white stripes, representing the original colonies.

Mr Trump was accused of hypocrisy following his attacks on NFL players for failing to respect the flag and kneel for the national anthem before games. The Republican also, notoriously, hugged an American flag after making a speech attacking illegal immigration.

Activist and songwriter Holly Figueroa O’Reilly said: “American flag’s stripes are red and white. Trump should know this, considering the fit he throws when someone kneels at a football game, ‘disrespecting the flag’.”

Twitter users were also quick to suggest Mr Trump was actually attempting to colour in the Russian flag, which is made up of three horizontal layers of white, blue and red, at a time when the FBI is investigating his campaign’s ties to Russia before the 2016 election..

The photo of the president’s flag colouring session was first tweeted by the secretary of state for health and human services, Alex Azar.

The opioid crisis is one of our top priorities at HHS, with a drumbeat of action on the full range of efforts where we can assist local communities. Today, I joined @POTUS & @FLOTUS in Ohio to learn how states and communities are responding to the challenge of opioid addiction. pic.twitter.com/NwxSoeNznA — Alex Azar (@SecAzar) August 25, 2018

The added blue line was quickly spotted online, as Twitter users speculated whether it was a simple mistake or a deliberate act.

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Several people spotted the resemblance to the colours of the Russian flag, and the flag of the Netherlands.

Maybe he was going for the Russian flag? #TraitorTrump pic.twitter.com/eS6IDoEWYI — Cris S (@ColombianCris) August 26, 2018

Meanwhile, Mr Trump’s supporters claimed the president was in fact paying tribute to the police with the added blue line.

Then this is why. He supports cops. Simple. pic.twitter.com/RKl2iKxXK7 — RobertTrader (@WethepeopleT) August 26, 2018

An alternative theory was he was issuing a coded message about John McCain a few days before the senator’s death from brain cancer.

This was a message about John McCain...

Look up USA Flags!

He's drawing: The flag for US Internal Waters

Particularly in reference to one born on sovereign areas outside consec 50 states like JOHN MCCAIN ->Panama Canal!!! US NAVY -Trump KNOWS flags, he was BORN on Flag Day! pic.twitter.com/1jtXFG6JDn — Lynette Johnson (@Profitigation) August 26, 2018

It was also claimed Mr Trump appeared to be trying to copy the child sat next to him at the table.

In fact, it would have been easier for the president to look at the flag pin he was wearing on his own jacket.

It follows a tough week for Mr Trump, with his former campaign manager Paul Manafort being convicted of fraud, lawyer Michael Cohen pleading guilty to paying “hush money” to a Playboy model and a porn actress alleging affairs with the president, and reports several allies have been granted immunity from prosecution in return for their testimony.