On 31 May 2010, an international incident broke out in the Mediterranean Sea when foreign activists trying to break the maritime blockade over Gaza, clashed with Israeli troops. During the struggle, nine Turkish activists were killed. In late September 2010 took place direct negotiations between Israel and the Palestinians without success. As a defensive countermeasure to the rocket threat against Israel's civilian population, at the end of March 2011 Israel began to operate the advanced mobile air defence system "Iron Dome" in the southern region of Israel and along the border with the Gaza Strip.