A U.S. official says that North Korea could hand in a long-awaited accounting of its nuclear past as early as Thursday.

That's the earliest date expected for a document that has become the symbolic linchpin for the North's nuclear disarmament deal with the United States and other countries.

The official spoke on condition of anonymity because the diplomatic discussions with the North are confidential. The United States is hoping for Thursday, but it is not yet clear exactly when the North will hand over the paperwork.

Once the document is in hand, the U.S. has promised to remove its sanctions on North Korea under the Trading With The Enemy Act and a terrorism blacklist.

The U.S. says the document from Pyongyang has been overdue since December 31st.