(JTA) — Another tunnel under Gaza has collapsed, killing a Hamas operative digging it, and the terrorist group’s military wing is blaming Israel. The tunnel collapse occurred on March 3 in southern Gaza. Days earlier, a tunnel collapsed in eastern Gaza, injuring five Hamas members. The Jerusalem Post said some Hamas operatives are blaming Israel, saying they have seen Israeli soldiers on the border using liquid explosives and “causing small earthquakes” to destroy tunnels. Seven tunnels have collapsed in the past two months, according to the Times of Israel, including one that killed a nephew of Hamas leader Mahmoud al-Zahar.

In January, senior Hamas leader Ismail Haniyeh announced at a funeral for seven Hamas operatives that were killed in a tunnel collapse that Palestinian “heroes” are digging tunnels to be used in future attacks on Israel. At that time, the Times of Israel reported that Hamas had more than 1,000 people working around the clock, six days a week, digging tunnels lined with concrete and “being dug 30 meters deep, with sophisticated engineering equipment and more advanced technological support, including engineers’ blueprints.”

Hamas’ vast network of tunnels, many leading into Israel, was a major issue during Operation Protective Edge, Israel’s 2014 war in the Gaza Strip. During the war, Israel destroyed more than 30 tunnels, which were used to smuggle weapons, as well as stage terrorist attacks and kidnappings inside Israel.