SEOUL, Oct. 17 (Yonhap) -- President Lee Myung-bak instructed aides Monday to conduct an "all-out review" of a project to build his post-retirement residence in southern Seoul, an official said, after the purchase of a tract of land under the name of his son sparked criticism.

Lee said it is "very regrettable" that the residence issue has "caused concern to many people" against his will and ordered an "all-out review" of the project to early conclude the issue, according to senior press secretary Choe Guem-nak.

Presidential security service chief Kim In-jong offered to resign over the matter, Choe said.

Following media revelations that Lee's only son bought the land in Naegok-dong in southern Seoul, opposition parties and critics have raised a series of suspicions, including how he was able to make the expensive purchase.

The presidential office has stressed Lee bought the land in Naegok-dong to build a residence and auxiliary security facilities after leaving office in early 2013, and that the son's name was used for security reasons because a contract bearing Lee's name would lead to the site's disclosure.

In an effort to calm criticism, the office has said that Lee would take over the land's ownership from the son and that it would consider downsizing the large site reserved for security facilities.

Despite the explanations, opposition parties have raised a string of suspicions, and even Rep. Hong Joon-pyo, head of Lee's ruling Grand National Party, said he would ask Lee to reconsider the project.