Iran has stepped up its efforts to smuggle weapons into the Gaza Strip by using floatable devices that it drops near the waters off the Gaza coast to be picked up by Palestinian fisherman, senior defense officials have told The Jerusalem Post. According to defense officials, Iran is now sending rockets and other advanced weaponry to Hamas and Islamic Jihad in the Gaza Strip by sea as well as via tunnels dug under the Philadelphi Corridor and connecting the Sinai peninsula with Rafah. Officials said that the Navy is doing a fairly effective job in curbing the smuggling by sea, but that there are some shipments Israeli forces did not succeed in intercepting. "They throw the weapons overboard in waterproof, sealed tubes which then float into the Gaza waters and are picked up by fishermen," one official said. "Sometimes Navy boats intercept them and sometimes they get through." In recent months, the IDF has noticed an increase in Iranian-made weaponry in the Gaza Strip, including rockets and mortars. Terror groups in Gaza recently were equipped by Teheran with two different types of mortar shells made in Iran - one 120 mm with a range of 10 kilometers like a Kassam rocket and another with a range of six kilometers. Defense officials told the Post that in recent weeks thousands of mortars have been smuggled into Gaza. Officials in Jerusalem said some of the weaponry now in Gaza was far too large to have been smuggled through tunnels burrowed from Sinai into Gaza, and that there was obviously an alternative route that was being used to smuggle weaponry into the area. In addition to providing weaponry, Iran is also training Hamas and Islamic Jihad terrorists, who have used the periodic openings at the Rafah Crossing with Egypt, as well as the collapse of the border with Egypt in January, to travel to Iran and train there in terror and guerrilla warfare. Officials said the weapons could take several routes from Iran to Egypt. One possibility is that the weapons are taken by boat from Iran to Egypt and then are smuggled into Gaza through tunnels or thrown into the waters off the coast and near the border. Another possible route is that the weapons are transferred by Iran to Syria, and then to Lebanon, where Hizbullah ships them by boat to Egypt. A branch of the Iranian Revolutionary Guards - called the Quds (Jerusalem) Force - is believed to be responsible for overseas operations, such as training Hizbullah and Palestinian terrorists and providing them with weapons. Meanwhile, a full closure was imposed Thursday on Gaza and the West Bank, effective midnight Thursday, for the duration of Pessah. A terror infiltration into the Kerem Shalom Crossing into Gaza was thwarted on Thursday by the IDF. Military sources said that three armed terrorists were spotted on their way to the crossing - the main conduit for food and medical supplies transferred to Gaza - and were intercepted by a force from the Bedouin Desert Battalion that was stationed nearby. One terrorist was killed and another was wounded in an ensuing gunfight. The foiled infiltration followed heavy violence on Wednesday when three IDF soldiers and close to 20 Palestinians were killed in clashes in Gaza. On Thursday, 10 rockets were fired into Israel, including a Grad-model Katyusha rocket that hit an open field south of Netivot. No one was injured in the attacks. Earlier in the day, two Islamic Jihad operatives were shot dead in the West Bank town of Kabatiya near Jenin. The IDF said troops surrounded a home in which the operatives were hiding and called on them to come out. The suspects refused and were killed in an ensuing exchange of fire.