Egypt's crackdown on the Muslim Brotherhood could lead it to carry out its own strikes against Gaza, Israeli army officers have said.

Israeli and Egyptian intelligence officials believe that Hamas is co-operating with Ansar Beit al-Maqdis, an Islamist group fighting in Sinai, which in recent months has sworn allegiance to Islamic State (IS) and could attract the support of the Muslim Brotherhood.

If Gaza were to become an operational hub of this new grouping, Egypt could decide to launch its own offensive on the territory.

In such a case, Israeli officers say that warfare could grow along the Israel-Egypt border, with IS launching rockets at the southern end, towards Eilat.

Meanwhile, inside Gaza, Hamas is struggling to contain the influence of Salafist groups that are increasingly identifying with IS.

A rocket launched from Gaza towards central Israel last week did not cause a new round of violence but it highlighted how fragile the situation currently is within the Gaza Strip.

The Grad rocket was fired by a wing of Palestinian Islamic Jihad (PIJ) in what was reportedly an internal dispute between rival groups within PIJ.

Apart from one Israeli citizen who was treated for shock, the rocket caused no damage or casualties.

The IDF responded with an air attack on three targets belonging to PIJ, Hamas and one smaller armed group. Three PIJ operatives connected to the rocket attack were arrested by Hamas in Gaza.

Senior Israeli officers have warned in recent days that the growing isolation of the main militant groups in Gaza could cause a new escalation.

Defence Minister Moshe Yaalon said last week that "Hamas better work to rein in any attempts at firing or else we will have to act in greater strength."

However, according to Israeli intelligence, Hamas itself is as divided as ever, with its political and military wings at loggerheads. Military chief Mohammed Deif is pushing for a renewed alliance with Iran and working closely with PIJ.