North Korea is stepping up its warlike rhetoric after the U.N. Security Council hit the country with tough, new sanctions.

North Korean leaders threatened to cancel a hotline and non-aggression pact with South Korea. They warned the country will retaliate with "crushing strikes" if enemies intrude into its territory.

These latest sanctions are also raising concern about faith-based groups working in the communist nation.

A State Department official said those groups have managed to get some needed assistance past Pyongyang.

Sen. Marco Rubio, R-Fla., also urged the State Department to remember persecuted North Korean Christians as it deals with the communist regime's nuclear threat.