GAZA - A Gaza farmer was killed and a second man was wounded by an Israeli tank shell on Friday, a Gaza health ministry spokesman said, on a day of heightened tensions ahead of planned protests by Palestinians along the border with Israel.An Israeli military spokesman confirmed the incident. "Overnight two suspects approached the security fence and began operating suspiciously and the tank fired towards them," the spokesman said.Palestinians in the Gaza Strip are planning to begin a six-week tent city protest to demand Palestinian refugees be allowed to return to what is now Israel. They have erected dozens of tents at five locations along the border.The Gaza health ministry spokesman said the farmer was killed and another was wounded near the town of Khan Younis. Residents there said he was gathering crops to sell later."Omar Samour, 27, was martyred and another citizen was wounded as a result of [Israeli] targeting of farmers east of Qarara village," the health ministry said.The military spokesman said Israeli troops had also fired towards two other men at another location along the Gaza border when they approached the fence trying to "interfere with security infrastructure" but he did not elaborate. One of the two was hit, he said. Gaza sources initially had no details.Israeli security forces are on heightened alert and Israel's military chief said in an interview on Wednesday more than 100 sharpshooters had been deployed on the Gaza border ahead of the planned mass demonstration near the frontier.The Israeli military, citing security concerns, enforces a "no go" zone for Palestinians on land in Gaza adjacent to Israel's border fence. Heavy earth-moving vehicles have built up dirt mounds on the Israeli side of the border and barbed wire has been placed as an additional obstacle against any mass attempt to breach the border into Israeli territory.Organizers from a number of factions, including Islamist Hamas, which dominates Gaza, hope thousands will answer their call to flock to tent cities in five locations along the sensitive border to call for a right of return of Palestinian refugees to what is now Israel.The March 30 date for the start of the protest marks "Land Day" commemorating the six Arab citizens of Israel who were killed by Israeli security forces during demonstrations in 1976 over government land confiscations in northern Israel.It is due to end on May 15, the day Palestinians call the "Nakba" or "catastrophe," marking the displacement of hundreds of thousands of Palestinians in the conflict surrounding the creation of Israel in 1948.