The White House is holding up delivery of a fleet of F-15 jet fighters to Israel.

The $18 billion sale of 50 fighter planes is “one of the largest arms deals with Israel in recent years,” The Wall Street Journal reported.

The sale had been delayed by two of four congressional leaders needed to sign off on major arms deals, but they removed their objections on May 22.

The next step was for the State Department to formally notify lawmakers about the sale. The administration hasn’t yet done that, White House and congressional officials said, according to the Journal.

The State Department denied it was holding up the sale, with an official telling the Journal, “There is no policy guidance to slow down transfers to Israel.”

The State Department official added, however, “We are looking tactically at the timing. It is not a question of whether, it is a question of when.”

Referring to last week’s Israel visit by Secretary of State Antony Blinken, Prime Minister Benjamin Netanyahu in a social media post on Tuesday told the Biden administration to stop slow-walking the delivery of vital arms for Israel’s war effort.

“When Secretary Blinken was recently here in Israel, we had a candid conversation. … I said it’s inconceivable that in the past few months, the administration has been withholding weapons and ammunitions to Israel,” Netanyahu said.

Netanyahu told Blinken during the June 10 meeting that Israel would fight even without U.S. support, but that the arms embargo gave Iran-backed Hamas and Hezbollah a strategic edge, raising the chances of a prolonged multi-front war in the Middle East.

Asked about Netanyahu’s remarks on Tuesday, Blinken didn’t refer to the F-15 sale, saying that a single shipment of 2,000-pound bombs remains under review, but that all of the other arms deliveries are moving forward.

On Wednesday afternoon, Prime Minister’s Office spokesman David Mencer told JNS that U.S. Ambassador to Israel Jack Lew informed Netanyahu that the ammunition and weapons that he had referred to in the video are “in the process of being delivered to Israel.”

The White House, miffed by Netanyahu’s comments, reportedly called off a scheduled “strategic dialogue” on Iran between Israeli and U.S. officials in Washington.

Mencer wouldn’t confirm the report, saying only that the U.S.-Israel relationship “is an extremely close relationship. … There will be times in that partnership when issues come up which tests that relationship and it’s normal for there to be disagreements.”

In early May, Biden officials announced the administration would withhold the bombs delivery due to its opposition to a large-scale ground offensive in Rafah, the last Hamas stronghold.

President Joe Biden delivered that message to CNN, saying he would halt the shipment of offensive weapons if Jerusalem went ahead with its counterterrorism operation in Gaza’s southernmost city.

Israel launched its Rafah operation in early May, but not the large-scale assault that the White House had feared. Instead, the incursion was limited in scope. Israeli officials and analysts say Israel may be nearing the end of that operation, turning to a still less-intense phase of the conflict.