South Korean automaker Hyundai Motor, which posted an earnings surprise in the first quarter, hit a rough patch with factory suspensions due to a global semiconductor shortage and labor backlash against a major U.S. investment.

According to industry sources, Hyundai is shutting down one of its Ulsan plants that manufactures the Avante and Venue on Tuesday and again on Thursday, due to a shortage of chips for airbag control modules.

Part of another Ulsan plant that makes the Tucson and hydrogen-powered Nexo was suspended for the second straight day on Tuesday.

Hyundai's affiliate Kia Motors was also forced to halt work at its Gwangmyeong plant for two days until Tuesday.

Meanwhile, labor unions at both Hyundai and Kia protested Hyundai's electric vehicle and autonomous driving-related investment plan worth eight trillion won in the U.S. ahead of the South Korea-U.S. summit on Friday.

The unions demanded that the company instead seek ways to reinforce domestic factory operations and stabilize employment.