Four Palestinians were shot dead on Wednesday by Israeli troops - three in the southern Gaza town of Khan Younis and one in eastern Gaza City, Palestinian medical sources said. An Israeli guard was earlier shot dead by Palestinian militants near the village of Idna, west of the southern West Bank town of Hebron, Israeli Radio reported. Palestinian medical sources said that a militant member of al Qassam Brigades - the Hamas movement's armed wing - was shot dead late Wednesday in Khan Younis during exchange of fire with Israeli soldiers. The Israeli army has been carrying a second large-scale military operation in Khan Younis in the southern Gaza Strip during the week. The first incursion last Friday and Saturday saw 11 killed. The second, carried out Wednesday, saw two Palestinian militants killed earlier, again in Khan Younis. The Israeli army said the operation would continue amid efforts to prevent Palestinian militants from launching homemade mortar shells and rockets at nearby Jewish settlements. Also on Wednesday a Palestinian was shot dead by Israeli troops near the borders between eastern Gaza Strip and Israel. Israeli troops and tanks rolled into the southern Gaza Strip's Khan Younis refugee camp early Wednesday morning, sparking gunfights with militants in which one Palestinian was killed, witnesses and Palestinian medical officials said. --SP 2306 Local Time 2006 GMT