The CIA secretly sent money to the Liberal Democratic Party in the 1950s and 1960s to help stabilize the LDP-led government and prevent a leftist administration from emerging, according to a U.S. document released Tuesday.

The document, titled "Foreign Relations of the United States, Vol. XXIX, Part 2," also suggests that some of the CIA money went to moderate members of the now-defunct Japan Socialist Party, the LDP's rival at the time, apparently to help them form a moderate breakaway.

It is the first time the U.S. government has formally admitted having a covert financial program for Japanese politicians, a State Department official involved in compiling the document said.

The LDP has denied the CIA give the party financial support.