Trump Mobile, the phone company launched by Donald Trump’s family business, has pushed back plans to deliver a $499 gold-coloured smartphone by the end of the year.

The T1 smartphone, described by the company as “proudly American”, was initially promoted as a US-made rival to devices from Apple and Samsung. Almost all smartphones sold in the US are made overseas, primarily in China and South Korea but also increasingly in India and Vietnam.

It remains unclear who could manufacture the T1 handset, given the low levels of domestic smartphone production in the US.