The Israel Defense Forces (IDF) countered Palestinian attacks with incursions against militant targets into the West Bank and Gaza Strip, adopting highly effective urban combat tactics. The IDF stressed the safety of their troops, using such heavily armored equipment as the Merkava heavy tank and armored personnel carriers, and carried out airstrikes with various military aircraft including F-16s, drone aircraft and helicopter gunships to strike militant targets. Much of the ground fighting was conducted house-to-house by well-armed and well-trained infantry. Due to its superior training, equipment, and numbers, the IDF had the upper hand during street fighting. Palestinian armed groups suffered heavy losses during combat, but the operations were often criticized internationally due to the civilian casualties often caused. Palestinian metalworking shops and other business facilities suspected by Israel of being used to manufacture weapons were regularly targeted by airstrikes, as well as Gaza Strip smuggling tunnels.