(Reuters) -Tesla's sales dropped for a sixth straight month in Sweden and Denmark in June, underscoring the challenges the EV-maker faces as competitors gain market share and CEO Elon Musk's popularity declines.

In Sweden, Tesla's registrations, which are a measure of sales, fell 64.4% in June from a year earlier.

Tesla's sales were also down 61.6% in Denmark, where the U.S. EV maker's revised Model Y sales fell 31.2% compared with last year to 1,155 cars, showing no signs of reviving the brand's fortunes.

The publication of Tesla's monthly car registration figures coincided with a renewal of a dispute between Musk and U.S. President Donald Trump regarding a sweeping tax-cut and spending bill.

Frankfurt listed shares of Tesla were down 5.6% at 0730 GMT.