(UNITED NATIONS) -- Twenty rockets were found hidden in a Gaza school run by a United Nations agency, the U.N. revealed Thursday.
The munitions were discovered Wednesday, the United Nations Relief and Works Agency said in a statement posted on its site Thursday. The announcement came as Israel and Hamas were in a tenth day of ferocious dueling that has left 227 people dead, only one of which were Israeli.
"In the course of the regular inspection of its premises, UNRWA discovered approximately 20 rockets hidden in a vacant school in the Gaza Strip," the agency said.
UNRWA, which supplies shelter and humanitarian aid in Gaza, condemned the storage of the weapons in its school and said, "This incident, which is the first of its kind in Gaza, endangered civilians including staff and put at risk UNRWA’s vital mission to assist and protect Palestine refugees in Gaza."
It said that they "informed the relevant parties and successfully took all necessary measures for the removal of the objects in order to preserve the safety and security of the school."
The agency didn't identify the location of the school, the types of rockets or who the "relevant parties" were.
The announcement bolstered Israeli claims that Hamas, the militant group that controls Gaza, has used schools, mosques and medical facilities as shields as it fires rockets at Israel.
Israel and Hamas resumed launching attacks at each other earlier Thursday after a five-hour long humanitarian pause allowed people in Gaza to rush to markets to stock up on supplies. The halt in the shelling was marred by a flurry of mortar shells lobbed at Israel from Gaza and an Israeli soldier was injured by a blast near the southern Gaza Strip. The Israeli forces held their fire except to respond with mortar fire after the soldier was wounded.
The tragedy of the fighting was underlined Wednesday when four Palestinian boys, aged 9 to 11, were killed by Israeli shells while playing on a Gaza beach.
The Israeli military said it thwarted an earlier attack by 13 Gaza militants who sneaked into Israel through a tunnel.
Lt. Col. Peter Lerner, a military spokesman, said the militants were identified about 820 feet inside Israel and were struck by Israeli aircraft. Lerner said the military believed at least one militant was killed in Thursday's strike. He said the remaining fighters appeared to have returned to Gaza through the tunnel.
This was the second time militants infiltrated Israel from Gaza. Israel killed four militants last week who entered from the sea.
The president said the United States "will use all of our diplomatic relationships to support closing a deal on a ceasefire."
Israel had halted its attacks for several hours earlier this week, but resumed its military campaign after Hamas fired dozens of rockets at Israel.
At least 1,685 people have been injured in Gaza since fighting broke out last week, the health officials said.
The battle has broken a two-year lull in hostilities between Israel and Hamas and was triggered by the slaying of three Israeli teens and revenge burning death of a Palestinian teen. Angry protests escalated to rocket launches and retaliatory air strikes.
Copyright 2014 ABC News Radio