After questioning the Polish captain, Israeli soldiers received permission to board the German-owned vessel and reviewed the ship's manifest, which showed about 40 of the boats 300 containers to be Iran Shipping Lines containers en route to Syria.
An inspection of some of the containers revealed wooden ammunition crates hidden amid sacks of industrial polyethylene. Following the discovery, Israel's navy escorted the boat to the port of Ashdod to inspect the rest of the cargo.
Military officials said the crew was unaware of the cargo's contents, and speculated that port officials in Egypt also didn't know.
"Syria and Iran's grave actions violate all international laws," Israeli President Shimon Peres said in a statement. "The ship's arrest is not only of critical military importance, but also of political importance – facts cannot be argued with."
A spokesman for the United Nation's Interim Force in Lebanon (UNIFIL) charged with overseeing the cease-fire and stopping weapons shipments, said his organization had no information beyond what it had read in the press about the seizure. The group's mandate confines it to Lebanon's territorial waters. He said UNIFIL's position is that allegations that the weapons were destined for Hezbollah are "unproven."
On Wednesday afternoon, Israel's military had inspected only about one-third of the containers. As dock cranes reaching about 10 stories high moved containers with the letters IRISL – the marking of the Iranian shipping company -- reporters were allowed to inspect the cargo.
Some of the containers were partially unpacked to show weapons crates hidden amid the polyethylene sacks. Next to others were stacks of crates with 122-millimeter and 107-millimeter Katyusha rockets, 106-millimeter artillery shells, mortars, and bullets.