The United States has reiterated its position that North Korea's denuclearization should come before a peace treaty can be signed to formally end the Korean War.

In a daily news briefing on Friday, White House spokeswoman Dana Perino said a peace treaty could result from a denuclearized Korean Peninsula at the end of the six-party talks process.

Perino also stressed an action-for-action approach in the process towards a permanent peace mechanism on the Korean Peninsula.

On allegations of nuclear cooperation between North Korea and Syria, Perino says the U.S. strongly opposes the transfer of nuclear material from North Korea to Syria.

She said any transfer of nuclear material is against the six-party nuclear agreement.