Jerusalem: At least 12 people were killed in the latest air raids on Gaza Strip by Israel's military on Tuesday, Al Jazeera reported, adding that 20 others sustained injuries in an operation conducted early morning.

At around 2 am (local time) on Tuesday (23:00 GMT on Monday), explosions targeting residential flats were reported throughout Gaza.

The Palestinian Islamic Jihad (PIJ) movement said that three of its leaders were killed, including their wives and several children, according to Al Jazeera.

Three senior members of the Palestinian Islamic Jihad movement were killed by the Israeli army in an early Tuesday morning bombing in which explosions ripped through Gaza under 'Operation Shield and Arrow', The Times of Israel reported.

Prior to the operation, Israeli residents of areas within 40 kilometres (25 miles) of Gaza were instructed to enter or stay near bomb shelters amid fears of retaliatory attacks, as raids continued to thunder across the Strip.

According to The Times of Israel, previous strikes on Islamic Jihad leaders have sparked barrages of rockets on Israeli civilians and intense battles with Israeli troops, some lasting several days.

Dozens of strikes were reported across the Strip in the ensuing hours, sending fireballs skyward as the army targeted terror training sites. The army called the campaign 'Operation Shield and Arrow'.

The bombings came after Adnan, a Palestinian Islamic Jihad activist, passed away last week after going on a hunger strike for almost three months. According to the Palestinian Prisoner's Society, Adnan had abstained from eating for 87 days as a form of protest against his imprisonment without cause.