Hamas loyalists and Egyptian troops opened fire along Gaza's volatile border Wednesday, leaving an Egyptian soldier dead and more than a dozen Gazans hurt in the bloodiest clash between the two sides in a year. Accompanied by a barrage of rocks, the shooting underlined the mounting tensions over Egypt's construction of an underground steel wall that could seal Gaza's southern border, block hundreds of smuggling tunnels and deprive Gaza's Hamas rulers of their only lifeline. Hamas is trying to rally Arab and Muslim public opinion against the barrier it has dubbed the “death wall.” Hamas-allied Muslim clerics have denounced the wall as “haram,” or forbidden by Islam, and protesters picketed Egyptian embassies in Lebanon and Jordan this week. Egypt, meanwhile, is adopting an increasingly defiant stance, saying that securing its border with Gaza is a matter of national security. In the past, Egypt had been less unequivocal and tried to play down its role, alongside Israel, in enforcing Gaza's border blockade. Wednesday's clashes began when several hundred Hamas supporters waving green Hamas flags marched toward Egyptian border fortifications to protest against the wall construction and Egyptian restrictions on an international aid convoy led by British legislator George Galloway. A senior Hamas official, Munir al-Masri, told the protesters that Egypt's actions were shameful. Moments later, people in the crowd started to throw rocks at Egyptian border guards, including an Egyptian position fortified with sandbags. At some point, Hamas police fired shots to disperse the crowd and shots were also heard from the Egyptian side of the border. It was not clear who fired first. Gunshots killed a 21-year-old Egyptian border guard stationed in a watch tower, according to the Egyptian news agency. Seven Palestinians were also hit by gunfire, including three who were seriously wounded, Palestinian hospital doctors said. Nine Egyptian guards and eight Gaza protesters were hurt by rocks and tear gas. It was the worst violence on the border since an Egyptian major was killed by Palestinian gunmen during Israel's offensive on the Gaza Strip in December 2008. Israel, meanwhile, said it has successfully completed testing its “Iron Dome” system to shoot down rockets fired from Gaza or Lebanon. Israel's devastating invasion of Gaza a year ago was aimed at stopping years of rocket fire. The Israelis say the new system can intercept rockets before they cross into Israeli airspace. The Israeli Defense Ministry did not say when it will be deployed. Gaza's borders have been frequent points of friction since Israel and Egypt imposed a blockade in June 2006, following the capture of an Israeli soldier by Hamas-allied militants. The closure was tightened after Hamas overran Gaza a year later, seizing the territory from Western-backed Palestinian President Mahmoud Abbas.