BEIRUT, JULY 1 -- A previously unknown group claimed responsibility today for the abduction two weeks ago of American journalist Charles Glass and accused him of spying for the U.S. government.

The authenticity of the statement, the first claim since Glass was kidnaped with two Lebanese on June 17, could not be established. It was not accompanied by any photograph or other evidence that its author is holding Glass.

The claim came in a communique, typewritten in Arabic and signed in the name of the Organization for the Defense of Free People. The note was slipped under the door of a correspondent in the city of Sidon for Lebanon's Voice of the Nation radio station, an editor of the station said.

The communique said the 36-year-old Glass was being held "for the purpose of investigation."

Immediately after the kidnaping, attention focused on the pro-Iranian Shiite Moslem group Hezbollah as Glass' captors. Although Hezbollah, or the Party of God, has denied taking Glass, Syria has kept pressure on it and on Iranians who work within the Lebanese Shiite community.

The chief of Syrian military intelligence in Lebanon, Brig. Gen. Ghazi Kanaan, has held meetings with senior representatives of Hezbollah to seek Glass' release, and a Hezbollah delegation traveled to Damascus today to discuss the affair with Syrian officials. Syria also has blocked Iranians from using their habitual routes across the Syrian border in traveling to and from Iran.

Lebanese fundamentalists have said Glass' kidnaping, only a few hundred yards from a Syrian Army checkpoint, is linked to tension between Iran and Syria. Syrian officers here have said they see the abduction as an affront to Syria and an attempt to discredit a Syrian security plan enforced in and around Beirut last February.