US President Donald Trump, with First Lady Melania Trump, speaks to the press at the White House. (AFP)

US President Donald Trump and first lady Melania Trump have only one request for their 13-year-old son Barron - "Don't vape".

"We haven't told him anything except, "Don't vape. Don't vape". We don't like vaping. I don't like vaping," Donald Trump said of Barron, New York Post reported.

The US President made the statement on the White House lawn before leaving for Baltimore when a reporter asked if he and the US first lady had discussed e-cigarettes or vaping with their teen son Barron.

Earlier on Wednesday, the Trump administration had announced that it would ban the sale of flavoured e-cigarettes or vaping liquids in a couple of weeks.

This move comes after as many as six people died in the United States and hundreds of others have fallen ill with mysterious lung diseases from vaping, the report said.

Under the Food and Drug Administration (FDA) ban, the companies that want to sell flavoured e-cigarettes will have to gain federal approval from the administration, which could take more than a year.