SINAI - Security chief said a military operation in Sinai against militants uncovered a bomb-making factory and netted 20 wanted men, including Palestinians and radical Islamists. The military and police deployed tanks and armoured vehicles in the peninsula last week to quell Islamist militants, who have repeatedly attacked police and a pipeline that exports gas to Israel. Saleh el-Masri, the North Sinai security chief, told the official MENA news agency that the captured men are suspected of involvement in an attack on a police station last month that killed a military officer and three bystanders. "Twenty wanted men have been captured so far, including Palestinians, and they are undergoing interrogation," he said. El-Masri said some of the captured men belonged to extremist Islamist cells. He added that a bomb-making workshop capable of producing explosive vests was found in the north along with a large quantity of explosives. Militants in the thinly-populated peninsula have attacked a pipeline that exports gas to Israel five times this year and have passed out flyers in which they claimed affiliation with the global Al-Qaeda network. Masri denied that the militants were members of Al-Qaeda, which has called for an Islamist state in Egypt. The army arrested four gunmen this week as they prepared to blast the pipeline again, and after more than 1,000 troops and police were deployed in the Sinai to uproot the militants.