The powerful sister of North Korean leader Kim Jong Un threatened Tuesday to launch high-profile provocations in response to the arrival of a U.S. aircraft carrier in South Korea and other U.S. military activities,

A visit by a U.S. aircraft carrier to South Korea prompted a warning from the sister of North Korea’s leader that Washington and Seoul “should not test” the communist regime.

The arrival of the carrier Carl Vinson and its strike group at the South Korean port of Busan was meant to display a solid U.S-South Korean military alliance in the face of persistent North Korean threats, and boost interoperability of the allies’ combined assets, the South Korean navy said in a statement.