Two Palestinian teenagers were found killed in the southern area of the besieged Gaza Strip, following two waves of Israeli air raids.

The two bodies of the two 17-year-old boys were retrieved in the city of Rafah on Sunday morning, Ashraf al-Qudra, spokesman for Gaza's health ministry, confirmed.

At least two other Palestinians have been wounded, one of whom is in critical condition, and are currently treated in a medical facility in Rafah.

In the past 24 hours, Israel said it had targeted 18 Hamas positions, in response to an "improvised explosive" device that detonated near the border with Israel early on Saturday, wounding four Israeli soldiers.

According to the Israeli army, six "large-scale attacks" were carried out on Hamas positions, including a tunnel that extends from Gaza to Israel.

Attacks that followed targeted positions in the town of Beit Hanoun, Rafah, Deir el-Balah, and Khan Younis in the southern part of the strip - on what Israeli media described as Hamas military installations.

The official Palestinian news agency WAFA reported that missiles launched from an Israeli F-16 attack aircraft damaged several civilian homes.

In a series of Twitter posts, Palestinian political party Hamas blamed Israel for the "escalation".

"The Palestinian resistance will not turn its back on protecting Palestinian people, and will continue to do defend it and confront enemy aggression," the movement governing the Gaza Strip said on Saturday night.

The encounter is the biggest of its kind since 2014, when Israel waged an assault on the strip that lasted for more than a month.

More than 2,250 Palestinians, including nearly 1,500 civilians, were killed and a further 11,000 were wounded in the July-August 2014 assault.

Commenting on Saturday's incident, Israeli Prime Minister Benjamin Netanyahu described the event as "severe".

"We will respond appropriately," he had warned in his statement.

The Israeli blockade of the occupied Gaza Strip, in its current form, has been in place since June 2007, when Israel imposed a land, sea and air blockade on the area.

Israel controls Gaza's airspace and territorial waters, as well as two of the three border crossing points; the third is controlled by Egypt.

Movement of people in and out of the Gaza Strip takes place through the Beit Hanoun (known to Israelis as Erez) crossing with Israel, and the Rafah crossing with Egypt.

Both Israel and Egypt have kept their borders largely shut and are responsible for further deteriorating the already-weakened economic and humanitarian situations.

Israel allows passage through the Beit Hanoun crossing only in "exceptional humanitarian cases, with an emphasis on urgent medical cases".

Al-Jazeera