WASHINGTON, May 15 (Xinhua) -- The U.S. House of Representatives passed a bill Thursday that requires President George W. Bush to certify that the Democratic People's Republic of Korea (DPRK) has not involved in nuclear proliferation before the Asian country is deleted from a U.S. terrorism blacklist.

    Under the adopted bill, Bush also has to certify that Pyongyang has provided a "complete and correct" and verifiable declaration of all its nuclear programs.

    The measure demonstrates the unease some lawmakers feel with the direction of the DPRK nuclear negotiations. It might interfere with the Bush administration's effort to settle a nuclear disarmament deal with Pyongyang, local mass media said.

    The U.S. Senate must pass it before sending it to Bush for his signature.

    The DPRK handed over its nuclear documents to U.S. envoy Sung Kim in Pyongyang on May 8. The documents are believed to be detailed technical logs from the DPRK's shuttered plutonium reactor.

    Under an agreement reached at the six-party talks in Beijing in February 2007, the DPRK agreed to abandon all nuclear weapons and programs and declare all its nuclear programs and facilities by the end of 2007, in exchange for diplomatic and economic incentives.

    However, the DPRK missed the deadline despite reported progress in its nuclear disablement and declaration. It was also accused of transferring nuclear technology to Iran and Syria, both have tense relations with Washington. The U.S. accusations are always denied by the three countries.