The Palestinian Islamic Jihad terrorist group is preparing a “significant” terrorist attack to undermine the ceasefire arrangement between Israel and Hamas, Yediot Aharonot reported on Monday..According to the report, security forces deployed along the Gaza security fence have noticed “unusual” activity by the group’s military wing, leading security officials to believe that the group might be planning a rocket barrage or breaching of the security fence in the coming hours or days. Islamic Jihad has denied the report, saying that "there is no truth to these reports. From time to time Israel tries to create confusion in the Palestinian arena, but these attempts will fail.”Palestinian Islamic Jihad (PIJ), the second largest group in the Gaza Strip after Hamas, has been assessed by military intelligence as a factor increasing the risk of an escalation in the blockaded coastal enclave, since it is not under the direct control of Hamas and acts independently for its own interests.The group is believed to be behind the last rocket barrage towards Israel on Saturday night when five rockets were fired toward southern Israeli communities after a relatively non-violent day when some 40,000 Palestinians rioted along the security fence marking Land Day and the first anniversary of the “Great Return” marches.PIJ is responsible for several violent attacks on IDF troops during the marches, including the first death of a soldier along the Gaza border since Operation Protective Edge in 2014.Staff Sgt. Aviv Levi was killed after he was shot in the chest by sniper fire near Kibbutz Kissufim. Another soldier was struck by sniper fire in the area less than a week after Levi was killed. In late January, an IDF officer was lightly wounded in the same area after his helmet was struck by sniper fire along the Gaza Strip security fence, in an attack for which PIJ claimed responsibility.The IDF has warned that both Hamas and PIJ have restored their military capabilities to their pre-2014 strength, and expect that in the next war the southern communities bordering the Strip would be incessantly pounded with rockets and mortar attacks.On Monday morning, Israel expanded the allowed fishing zone for Gazans to a range of between 22 km. to 28 km. after it was completely closed last week as the result of a long-range rocket fired by Gazan terrorists, which destroyed a family home in central Israel, wounding eight civilians.The rocket attack sparked a round of violence between Israel and Hamas and led to Israel deploying three infantry brigades and an artillery unit to enhance the Southern Command, as well as canceling the leave of all combat units currently assigned to the command.A tense calm has been holding in the South, with reports of a ceasefire deal mediated by Egypt in the works.According to reports, part of the deal was the expansion of the fishing zone which, according to Yediot is a range not seen since the Second Intifada.The Coordinator of Government Activities in the Territories (COGAT) said that the expansion of the fishing zone is part of a policy to prevent humanitarian deterioration in the Gaza Strip and of a “policy that distinguishes between terrorism and the civilian population.”“The implementation of the move is conditional on the fishermen in Gaza honoring the agreements. It will not be possible to deviate from the ranges that were agreed upon, and any deviation will be handled accordingly,” COGAT said.In addition to the expanded fishing zone, Israel reopened the Kerem Shalom and Erez border crossings on Sunday after they were closed last Monday.