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.

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.

Tesla Inc.'s European sales continue to decline, with a 61.57% drop in Denmark in June as poor sales globally add to concerns.