U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov discussed the importance of "a strong and united international response" to North Korea's fourth nuclear test, the State Department said Wednesday.

The North's nuclear test was one of the topics for Kerry's meeting with Lavrov in Zurich, Switzerland, along with Syria and Ukraine, the department said in a readout.

"They discussed the importance of a strong and united international response to North Korea's nuclear test in defiance of Security Council resolutions," it said.

Cooperation from Russia is key to the U.N. Security Council's push to adopt a new sanctions resolution aimed at punishing Pyongyang because Moscow is one of the veto-holding permanent members of the Security Council, along with Britain, China, France and the U.S.

Russia is also a member of the six-party talks aimed at ending the North's nuclear program. (Yonhap)