The Wall Street Journal reports: White House and State Department officials who were leading U.S. efforts to rein in Israel’s military campaign in the Gaza Strip were caught off guard last month when they learned that the Israeli military had been quietly securing supplies of ammunition from the Pentagon without their approval.

Since then the Obama administration has tightened its control on arms transfers to Israel. But Israeli and U.S. officials say that the adroit bureaucratic maneuvering made it plain how little influence the White House and State Department have with the government of Israeli Prime Minister Benjamin Netanyahu —and that both sides know it.

The munitions surprise and previously unreported U.S. response added to a string of slights and arguments that have bubbled behind the scenes during the Gaza conflict, according to events related by senior American, Palestinian and Israeli officials involved.

In addition, current and former American officials say, U.S.-Israel ties have been hurt by leaks that they believe were meant to undercut the administration’s standing by mischaracterizing its position and delay a cease-fire. The battles have driven U.S.-Israeli relations to the lowest point since President Barack Obama took office.

Now, as Egyptian officials shuttle between representatives of Israel and Hamas seeking a long-term deal to end the fighting, U.S. officials are bystanders instead of in their historic role as mediators. The White House finds itself largely on the outside looking in.

U.S. officials said Mr. Obama had a particularly combative phone call on Wednesday with Mr. Netanyahu, who they say has pushed the administration aside but wants it to provide Israel with security assurances in exchange for signing onto a long-term deal.

As a 72-hour pause in the fighting expired at midnight Wednesday, a senior Hamas official said negotiators agreed to another cease-fire, this one of five days. The cease-fire was holding on Thursday.

The frayed relations raise questions about whether Mr. Obama and Mr. Netanyahu can effectively work together. Relations between them have long been strained over other issues, including Mr. Obama’s outreach to Iran and U.S.-backed peace talks with the Palestinians.

Today, many administration officials say the Gaza conflict—the third between Israel and Hamas in under six years—has persuaded them that Mr. Netanyahu and his national security team are both reckless and untrustworthy.

The watershed moment came in the early morning in Gaza July 30. An Israeli shell struck a United Nations school in Jabaliya that sheltered about 3,000 people. Later that day, it was reported in the U.S. that the 120-mm and 40-mm rounds had been released to the Israeli military.

“We were blindsided,” one U.S. diplomat said.

White House and State Department officials had already become increasingly disturbed by what they saw as heavy-handed battlefield tactics that they believed risked a humanitarian catastrophe capable of harming regional stability and Israel’s interests.

They were especially concerned that Israel was using artillery, instead of more precision-guided munitions, in densely populated areas. The realization that munitions transfers had been made without their knowledge came as a shock.

“There was no intent to blindside anyone. The process for this transfer was followed precisely along the lines that it should have,” another U.S. defense official said.

Then the officials learned that, in addition to asking for tank shells and other munitions, Israel had submitted a request through military-to-military channels for a large number of Hellfire missiles, according to Israeli and American officials.

The Pentagon’s Defense Security Cooperation Agency, or DSCA, was about to release an initial batch of the Hellfires, according to Israeli and congressional officials. It was immediately put on hold by the Pentagon, and top officials at the White House instructed the DSCA, the U.S. military’s European Command and other agencies to consult with policy makers at the White House and the State Department before approving any additional requests.

A senior Obama administration official said the weapons transfers shouldn’t have been a routine “check-the-box approval” process, given the context. The official said the decision to scrutinize future transfers at the highest levels amounted to “the United States saying ‘The buck stops here. Wait a second…It’s not OK anymore.’ “