285. Memorandum From the Director of the Bureau of Intelligence and Research (Hughes) to Acting Secretary of State Katzenbach1


  • INR Comments on the USS Liberty Incident, June 8

According to a radio report from the USS Liberty, two unidentified delta-wing jet fighters orbited the ship at 0650Z on June 8 at an estimated altitude of 5000 feet and at a distance of two miles. A subsequent sitrep from the Liberty establishes the following chronology for the air and surface attacks: 1) at 1205Z, the ship was attacked by unidentified jet fighters, believed to be Israeli, which made six strafing runs on the ship; 2) at 1225Z, three torpedo boats, one identified as Israeli (hull number 206–17) approached the ship from the starboard quarter at high speed; 3) at 1227Z, the attacking boats launched a torpedo and strafing attack, 4) one torpedo struck the Liberty at approximately 1228Z; 5) at 1255Z Israeli helicopters orbited the ship at a range of 500 yards. At 0650Z, the Liberty’s position was 31 degrees 27 minutes N, 34 degrees 0 minutes E, at 1203Z, the ship’s position was 31 degrees 35 minutes N, 33 degrees 29 minutes E. These positions are, respectively, 15 and 23 nautical miles due north of the point on the UAR coast approximately [Page 475] midway between the towns of al-’Arish and al-Shu’ts. Al-Shu’ts is located within the UAR adjacent to the Gaza strip (see attached map).2

No traffic has appeared pertaining to Israeli military communications in this zone before and during the air and sea attacks on June 8. (We are checking further.) Our first intercept is logged at 1231Z, presumably three minutes after the torpedo attack; this message is the first in a series of commutations believed to have been conducted between Israeli ground radar-control stations and helicopters. The 1231Z message refers to “a warship that we attacked,” and directs the helicopters to attempt to rescue vessel crew members reportedly in the water. At 1234Z, the ground control station reported that the ship had been identified as Egyptian. (We do not know the basis of this identification.) At 1256Z, the helicopter pilots were ordered to report the nationality of any crew members rescued. At 1302Z, an Israeli ground station, responding to an unaudited message, asked: “did it clearly signal an American flag?” and requested a further check.

In a separate report from USDAO Tel Aviv, a reliable American source was told by a senior Israel Aircraft Industries (IAI) official that on the morning of June 8 he heard IDF transmissions at air-to-ground frequencies. An aircraft reported sighting a ship, was ordered to investigate, and reported back that the ship had a US flag. The aircraft was ordered to recheck and made a second and possibly a third pass, confirming at least for a second time that the flag was US.

The following conclusions appear warranted by the foregoing information: 1) we cannot determine with certainty that the jets that orbited the Liberty at 0650Z on June 8 were Israeli. From the ship’s location at that hour, however, it would appear probable that the aircraft were Israeli rather that Egyptian, since Israel exercised effective control of adjacent air space on June 8. 2) In the absence of time references, we cannot establish from the USDAO report whether the messages audited by the IAI official pertain to the 0650Z overflight, an unreported pre-attack overflight, the attack period or the post-attack period. From the context of these messages, however, they do not appear to be the helicopter-ground control communications available to us as COMINT. 3) In six strafing runs, it appears remarkable that none of the aircraft pilots identified the vessel as American (or at least non-UAR). 4) The torpedo boat attack was made approximately 20 minutes after the air attack. The surface attack could have been called off in that time had proper air identification been made. 4) Liberty crew members were able to identify and record the hull number of one of the small, fast moving torpedo boats during the two minutes that elapsed between their attack run and the launching of the first torpedo, but the Israeli boat commanders apparently failed to identify the much larger and more easily identifiable Liberty (11,000 tons, 455 feet long, large identification numbers on hull). 6) The Liberty sustained the air attack at [Page 476] 1205Z and the surface attack at 1225Z. According to COMINT (intercepted by a US Air Force Station), Israeli ground control stations in contact with the helicopters did not ascertain the Liberty’s identity until 1302Z, some 58 minutes after the initial encounter. This time lapse, taken in conjunction with the numerous intervening messages indicating doubt on the part of ground control officers as to the nationality of the ship, points to an extraordinary lack of concern on the part of the attackers as to whether the target was hostile. Indeed, the intercepted air-ground dialogue occurring between 1231Z and 1302Z suggests that Israeli ground controllers may have begun to be apprehensive about the possibility of a mistake. The receipt of unaudited messages either from the attacking aircraft or torpedo boats could have raised this question among Israeli ground controllers and led to the rather extensive dialogue that we have intercepted concerning the identification of “rescued crew members”. For example, in one instance a ground control station orders at 1307Z: “If they speak Arabic and are Egyptians, take them to al-Arish. If they speak English and are not Egyptians, take them to Lydda [near Tel Aviv].”3

  1. Source: NSA Archives, PCG, ACC 33824, USS Liberty Incident. Top Secret; Trine.
  2. Not reproduced.
  3. Brackets in the source text.