American International Group Inc is close to selling its Japanese headquarters for about $1 billion and the expected buyer is a Japanese insurance company, the Wall Street Journal reported, citing people familiar with the matter.

With Japanese markets closed for the Golden Week holidays until Wednesday, the exact timing of a deal was unclear, the paper said.

The sale of the headquarters would be one of the largest divestitures AIG has made to pay off its U.S. government debt, the paper said.

A sale of the AIG's airplane leasing business, International Lease Finance Corp., may also be close, the paper said, citing people familiar with the matter.

AIG's U.S. office did not immediately respond to a Reuters e-mail, that was sent outside of normal business hours, seeking comment.

(Reporting by Jennifer Robin Raj in Bangalore; Editing by Muralikumar Anantharaman)