U.S. Says It Did Not Help Israel Seize Ship
The officials cautioned that they had no evidence at this point that the weapons were destined for the Palestinian Authority, as claimed by Israel, and that it was more likely they were headed for the anti-Israeli Lebanese Shiite group Hezbollah.

One senior official said he assumed that the ship originated in Iran, but he acknowledged that American intelligence began tracking the ship at sea and not from an Iranian port, so he could not be sure. Another senior official said it was too early to speculate on either the origin or the destination of the weapons.
http://www.nytimes.com/2002/01/05/international/middleeast/05SHIP.html