Pence made the pledge to a high-level State Department conference on religious freedom, which came weeks after President Donald Trump met North Korean leader Kim Jong Un for the third time and agreed to jumpstart working-level negotiations.

"You can be confident, as President Trump continues to pursue the denuclearization of North Korea and a lasting peace, the United States will continue to stand for the freedom of religion of all people of all faiths on the Korean peninsula," said Pence, a conservative Catholic who is popular with Trump's evangelical base.

Pence noted that Open Doors, an advocacy group for persecuted Christians, has ranked North Korea as its worst violator for 18 straight years.

North Korean officials vow to "'wipe out the seed of Christian reactionaries' and possession of a Bible is a capital offense," Pence said.

Trump has voiced fondness for Kim, even saying that they two are "in love," as he seeks a potentially historic accord.

North Korea often scoffs at foreign criticism and accuses ill-wishers of trying to scuttle diplomatic efforts.

Earlier this week, North Korea warned that the resumption of talks could be affected by military exercises between the United States and South Korea.