The U.N. Security Council has voted to tighten sanctions on North Korea in response to their fifth and largest nuclear test.

The council unanimously approved the sanctions resolution on Wednesday with diplomats calling it a significant step forward.

The new sanctions target North Korea's hard currency revenues by placing a cap on coal exports, cutting them by at least 62 percent.

Diplomats said the new sanctions further clarify that the "livelihood" exemption, which allowed the Chinese imports, is meant only to protect the livelihoods of those currently living inside North Korea, not Chinese people or companies doing business with the country.

North Korea conducted its most recent atomic test in September, defying both tough international sanctions and long-standing diplomatic pressure to curb its nuclear ambitions.