Malnutrition rates among children in the Gaza Strip have doubled since Israel imposed sharp restrictions on the entry of food in March, the U.N. said Tuesday.

The war began when the armed group Hamas attacked Israel, resulting in the deaths of approximately 1,200 people and the abduction of 251 others to Gaza. As of now, out of the approximately 50 remaining hostages, it is estimated that only around 20 people are still alive.

Six children waiting for water are among those killed in an Israeli air strike, emergency service officials say.