"This is an Israeli missile ship, please follow my instructions," Lt. Yoav calls sternly into a microphone on the bridge of the INS Lahav (Blade) Tuesday. "Stop at your current position and do not proceed any further." Lt. Yoav is speaking with the Sierra Uniform, a yacht flying a Turkish flag as it tries to sneak by into Beirut Port. That is what the Lahav, a Sa'ar 5-class missile ship, has been doing since last Wednesday - blockading Beirut. On Tuesday, The Jerusalem Post accompanied the ship as it laid siege to Lebanon, 50 nautical miles from Beirut. The ship, part of the navy's Third Flotilla, has been serving as the command post for Cpt. Dani, commander of the squadron and the officer in charge of blockading Lebanon. Israel has imposed an air-sea-land siege on Lebanon in an effort to pressure the Lebanese government to release the two IDF soldiers captured by Hizbullah on July 12. The siege is also meant to stop Hizbullah from receiving new weapons from Syria and Iran or from smuggling the captives out of Lebanon. Cpt. Dani oversees all the navy's operations in Lebanon from his command post aboard the Lahav, including the blockade and the shelling of Hizbullah outposts near Beirut. "Our operations range from stopping ships from entering Lebanon to bombing Hizbullah outposts and rocket launchers," he explains. "Per the instructions of the political echelon, our main focus is on destroying Hizbullah infrastructure and in maintaining the naval siege imposed on Lebanon." Ten miles away, the navy has set up a "waiting area" for ships that have tried to leave Lebanon, says Lt. Zviel, one of the ship's deputy commanders. On Tuesday, eight ships were there, waiting for the navy to let them leave the region. The Sierra Uniform, carrying journalists, had tried to make it to Lebanon earlier in the week. Warships from around the world, Cpt. Dani says, have been flocking to the region ever since war broke out with Lebanon last week. "People want to be where the action is," he says. The navy has yet to fire at a ship that has refused to heed orders, but officers on board the Lahav insist that they will do so if necessary. On Tuesday, two Greek warships were allowed into Lebanon to evacuate their nationals. The navy has allowed other ships to enter and leave, mostly for humanitarian purposes. But, as the ship's skipper Cmdr. Tzahi Appleman says, "We are in charge of the sea." Down on the lower decks of this missile ship - Israel's largest - lies the Combat Information Center, a dark, cold room where officers track the merchant vessels trying to enter or leave Lebanon. The room, packed wall-to- wall with plasma screens displaying radar images, is also home to the ship's weapon-control systems. This missile ship, as well as some 10 like it, is armed with Harpoon sea-to-sea missiles, torpedoes, and anti-missile defense systems. One of those systems, the Rafael-developed Barak anti- missile system, has come under public scrutiny after an Iranian radar-guided missile launched by Hizbullah struck the INS Hanit (Spear) off the Beirut coast on Friday, killing four sailors. The Barak system, which defense industry sources said has a 99 percent success rate, was, the navy later admitted, operational at the time of the attack, although in a particular mode that did not enable it to intercept the incoming missile. The navy has learned its lesson, and on Tuesday the system was fully operational. Hizbullah, Cpt. Dani says, has also used artillery to fire at the numerous Israel Navy ships off the Lebanese coast. To prevent additional missile attacks, the navy and the IAF have, over the past few days, destroyed all the coastal radar stations belonging to the Lebanese army, which Israel says has been cooperating with Hizbullah. "We are not taking any chances following the attack on the Hanit," Cpt. Dani says. "There are always surprises in war, but from now on we are not taking any risks."