For a second time this week, Israel's military struck what it said were Hamas sites in the Gaza Strip in retaliation for "arson balloons" sent into Israeli territory.
The violence earlier this week was the first since a cease-fire between Israel and Hamas ended 11 days of fighting that left more than 240 Palestinians and 12 Israelis dead last month.
The Israel Defense Forces, or IDF, said Thursday that fighter jets struck "military compounds and a rocket launch site belonging to the Hamas terror organization in Gaza city and Khan Yunis."
The military said the airstrikes were in retaliation for incendiary balloons sent from the Gaza Strip at Israel.
The IDF on Wednesday also said it conducted airstrikes against Hamas compounds in Gaza over balloons. The Israeli fire department said the balloons caused 20 fires.
Hamas is a militant group that runs the Gaza Strip and is considered a terrorist organization by Israel and the U.S. The Israeli military said it holds Hamas "responsible for all events transpiring in the Gaza Strip."
Also Thursday, sirens sounded in southern Israel. The IDF said they were not triggered by rockets but by other incoming fire.
The Associated Press reported that surveillance video it obtained showed what appeared to be heavy machine-gun fire into the air from Gaza, which could have been attempts to shoot down aircraft. It reported that other video showed projectiles being fired from Gaza, but it was unclear what kind.
In May, thousands of rockets were fired from the Gaza Strip at Israel, sending people running to bomb shelters, and Israel conducted devastating airstrikes that flattened buildings and brought widespread devastation to the already impoverished Gaza Strip.
The fighting began after Israeli police raided Jerusalem's Al-Aqsa Mosque compound during Ramadan, the Muslim holy month. Hamas fired rockets into Israel, and Israel responded with an airstrike campaign.