The IDF denied on Tuesday that a house on a western Negev kibbutz was hit accidentally during an IAF helicopter attack on a Gaza training base overnight Monday. After a shell went through the roof of the house and landed next to one of the residents, causing no casualties, members of the kibbutz claimed to have found casings from 20 mm. shells, which are commonly used by IAF warplanes. They concluded that they were remnants of the strike. Later in the day, however, an IDF team conducted an inquiry at the site and came to the conclusion that the shells had in fact been fired by Palestinians from the Gaza Strip. Palestinian medical officials reported three Hamas operatives killed and one wounded in the IAF strike. According to Moaiya Hassanain of Gaza's Health Ministry, one person was killed on the spot and two later died of their wounds. The army confirmed carrying out the attack against the Hamas position in the coastal town of Deir el-Balah. The attack was a response to an earlier mortar shell attack that hit a house in the western Negev. Hamas claimed it fired at IAF warplanes with heavy machine guns. In a separate incident, a Palestinian gunman was killed in an exchange of fire with Golani Brigade troops near the Kissufim Crossing. None of the soldiers was wounded. On Tuesday afternoon, Palestinians fired three mortar shells into the western Negev. The shells landed close to the Gaza security fence, causing no casualties or damage. In the West Bank overnight, IDF troops arrested three Palestinian fugitives. One man was arrested in Nablus, a second in Idna, west of Hebron, and a third in Tubas, southeast of Jenin. The three were taken for interrogation.