Israel on Sunday prevented 15 trucks loaded with different kinds of medicines from passing through one of Gaza Strip crossings, a Palestinian health ministry official said.

Mo'aweya Hassanein, chief of emergency and ambulance services in the Palestinian health ministry, said in a statement that the Gaza Strip has been under a strict Israeli blockade for 13 days.

"The medical situation is worsening and we are living in a severe humanitarian crisis as Israel prevented the entrance of 15 trucks loaded with medicine from the West Bank into Gaza," said Hassanein.

Israel closed down all Gaza Strip commercial crossing points less than two weeks ago after violence flared up between Israel and Gaza militant groups, which were observing a six-month truce brokered by Egypt.

The ceasefire was declared effective in the Gaza Strip on June 19, which calls on Israel to loosen the leash of the coastal enclave in exchange for an end of Palestinians rocket attacks against the Jewish state.

"We have a shortage in 300 different kinds of medicines, and we are threatened to go through a severe crisis if we run out of all kinds of medicines," said Hassanein.

Hassanein said there are over 400 Gaza patients, mainly those who suffer from cancer and heart problems, in urgent need of medical treatment in Israeli or Arab hospitals, adding "Israel doesn't let them leave Gaza."

Israel insists that it would reopen Gaza crossing points, only if Gaza militants stop launching homemade rockets from the Gaza Strip at southern Israeli communities and cities.

Meanwhile, the Popular Committee to Challenge the Israeli Blockade called on the United Nations Secretary General Ban Ki-moon to visit the impoverished Gaza Strip, home to some 1.5 million aid-dependent Gazans.

"There are 1.5 million Palestinians who face slow death everyday due to the Israeli blockade. The world, mainly the United Nations, are responsible to rescue the lives of women and children," said the committee in a statement.