More than 20 people were injured and several homes destroyed by a large explosion Saturday in a residential area of the Hamas-ruled Gaza Strip, Palestinian officials said.

The source of the accidental explosion was apparently the home of a member of one of Gaza's armed groups.

"An explosion occurred in a house in Beit Hanoun this morning, resulting in a number of injuries," the interior ministry said, adding that an investigation had been launched into the cause of the blast.

Medical sources said more than 20 people were injured, two of them seriously.

Witnesses said several homes were damaged as a result of the explosion in the home of an "activist". Police cordoned off the area.

There was no immediate official explanation of the explosion, but the Israeli military said it was the result of militants "storing weapons in residential homes".

Houses "have been turned into warehouses for weapons... and missiles for terrorist organisations, and those who pay the price in the end are innocent civilians," the military's Arabic-language spokesman, Avichay Adraee, said on Twitter.

Islamist group Hamas seized control of Gaza from rival Palestinian movement Fatah in a near civil war in 2007.

Since then, Hamas has fought three devastating wars with Israel, which has maintained a crippling blockade on the territory of some two million people.