Israeli Air Force jets launched airstrikes on the Gaza Strip after a missile fired from Gaza landed in the Lachish Regional Council near the port city of Ashdod.
There are no reports of damage or casualties in the Israeli city, although a 15-year-old girl was taken to to Barzilai Medical Centre in nearby Ashkelon suffering from shock.
A Reuters correspondent, Nidal al-Mughrabi, in the Gaza Strip said that the IAF targeted Islamic Jihad and Hamas training facilities.
Israeli sources said the missile was likely to have been fired by Islamic Jihad, to mark the appointment of a new commander for the northern part of the Gaza Strip.
According to The Times of Israel, the new commander was supposed to start his new position on 26 May, but he was opposed by his predecessor, sparking clashes.
The new commander's men then kidnapped two operatives working under the former commander and, in retaliation, the predecessor's followers decided to fire rockets at Israel.
Irrespective of that, Israeli government sources made it clear that they held Hamas responsible for all attacks launched from the Gaza Strip.
After the Gaza missile attack, the Jerusalem Post reported that sirens were heard in other towns including Lakhish. On social media there are photographs of people apparently running to bomb shelters. Some residents said they heard several explosions.
During a 50-day war in July and August 2014, Hamas fired thousands of missiles from the Strip, but since the ceasefire there have been very few attacks launched on Israel. If confirmed, today's strike would be the longest-range missile to strike Israeli soil since the war ended.
No group has yet claimed responsibility for the attack.