A Palestinian boy mourns relatives killed in Israeli strikes on the Bureij refugee camp in Gaza Strip. AFP

"Five martyrs and a number of wounded were recovered after the occupation targeted Ibn Al Haytam School in the Shujaiya neighbourhood" of Gaza City, the agency said in a statement.

It is the latest in a series of Israeli strikes on school buildings housing displaced Gazans.

On Saturday the civil defence agency said five were killed in a strike on Gaza City's Shuhada Al Zeitun School.

Another strike on the United Nations-run Al Jawni School in central Gaza on September 11 drew international outcry after the UN agency for Palestinian refugees said six of its staffers were among the 18 reported fatalities.

In a separate development, Palestinian President Mahmoud Abbas will meet with Spain's prime minister and king during a two-day visit to the European country that begins on Wednesday, his first since Madrid formally recognised a Palestinian state in May.

Abbas is stopping in Madrid at Spain's invitation before heading to New York for the United Nations General Assembly, according to an official in his office.

His visit comes after Spain, along with Ireland and Norway, on May 28 formally recognised a Palestinian state comprising the Gaza Strip and the West Bank.

Spain's leftist government then announced that a first bilateral summit between Spain and Palestine would be held before the end of the year, and the first Palestinian ambassador to Spain presented his credentials on Monday to Spanish King Felipe VI.

Spanish Prime Minister Pedro Sanchez has said the recognition of a Palestinian state is "not against anyone, least of all Israel", but the move led to a further deterioration in ties between the two countries.

Agence France-Presse