A bipartisan group of U.S. senators on Wednesday warned North Korea of further economic sanctions in response to any provocation.

At a news conference on Capital Hill, Chris Van Hollen (D-MD) said regardless of what the North Korean thinking is, it's important to send a very clear message that the U.S. will respond to North Korean aggression by further ratcheting up economic pressure. 

Van Hollen and three other senators also criticized China and Russia's call for easing sanctions against the North, stressing that tougher sanctions are needed to bring Pyongyang back to the negotiating table. 

Van Hollen said rather than easing sanctions and relieving the pressure on North Korea to come to the negotiating table in good faith to denuclearize the Korean Peninsula, they need to "put teeth" in the "very leaky" sanctions regime currently in place.

The four senators spearheaded new legislation calling for further sanctions on Pyongyang as part of an annual defense policy bill that passed the Senate on Tuesday.