Thousands of Native Americans died on the Trail of Tears - is Trump making a joke about it?

US Senator Elizabeth Warren formally announced her candidacy for the White House on Saturday (Sunday NZ time), and hours later President Donald Trump weighed in on his newest campaign opponent, in what has been described as a joke about the Trail of Tears.

Soon after the Massachusetts senator's campaign announcement, Trump tweeted:

"Today Elizabeth Warren, sometimes referred to by me as Pocahontas, joined the race for President," he wrote on Twitter. "Will she run as our first Native American presidential candidate, or has she decided that after 32 years, this is not playing so well anymore? See you on the campaign TRAIL, Liz!"

The president's use of the word trail in all caps has seen by some as a potential reference to the Trail of Tears, the forced relocation of Native Americans from their homelands in the Southern United States to reservations in Oklahoma in the 1800s.

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Thousands of Native Americans died during the event.

Andrew Jackson was the president who signed the Indian Removal Act into law in 1830. Trump picked a portrait of Jackson for Oval Office in 2017.

This isn't the first time Trump mocked Warren about her claims of Native American ancestry in a tweet.

US President Donald Trump has frequently attacked US Senator Elizabeth Warren on Twitter.
US President Donald Trump has frequently attacked US Senator Elizabeth Warren on Twitter.

In January, after Warren posted a video on Instagram saying that she was forming an exploratory committee for a presidential run, Trump tweeted:

"If Elizabeth Warren, often referred to by me as Pocahontas, did this commercial from Bighorn or Wounded Knee instead of her kitchen, with her husband dressed in full Indian garb, it would have been a smash!"

Warren apologised on Wednesday for "not having been more sensitive about tribal citizenship" after The Washington Post published a 1986 Texas bar registration card where she listed her race as "American Indian."

It was at least the third time in a week that Warren has apologised for her past self-identification.

* This story has been updated as Donald Trump's intention with the use of the word 'TRAIL' is not clear.