A passenger bus was stationed Wednesday morning at a parking lot near Tel Aviv's harbor as part of Israel's largest emergency exercise. Police simulated a situation in which armed terrorists took hold of the bus and were holding hostages. A day after sirens were activated nationwide during the emergency exercise, OC Home Front Command Maj.-Gen Yair Golan said Wednesday that there were "gaps" in the siren system and that the IDF was looking into different technologies to improve its range. Speaking at a press conference at Home Front Command headquarter in Ramle, Golan said that 219 complaints had been filed by citizens who claimed to have not heard the sirens that were activated 10 a.m. Tuesday morning. Golan said that the IDF was looking into the feasibility of sending SMS text messages to all Israeli cell phones in the event of a real missile attack, alongside the sirens. He stated that hundreds of additional sirens would be installed throughout the country during the coming year. During Tuesday;s exercise over 1,500 were activated, he said. "There are still gaps in the warning system," Golan said "We have spent the past two years since the Second Lebanon War to improve the system, but we understand that the state of Israel will need to make more improvements and to technologically upgrade the system." Other alternatives that have been proposed are the distribution of beeper alert systems or using radio, TV and the internet as another means of transmitting the alert. Golan downplayed media reports of an increased tension between Israel and its neighbors due to exercise. "There is no mysterious intent behind the exercise and I think that this message has been [understood] by our neighbors," he said. Golan spoke to reporters at a newly built Home Front Command studio from which IDF officers will pass on messages to the public in the event of a war. Regarding the cabinet decision last week to redistribute gas masks to the public, Golan said that it could take up to five years until the entire public is resupplied with the masks. He said that following the cabinet decision, a multi-year plan would be formulated which would regulate the production and distribution as well as calculate the necessary budget for the masks. "There will not be an immediate solution tomorrow morning," he said. "It will take time, possibly three to four, or to five years until 100 percent of Israel receives the masks."