White House national security communications adviser John Kirby warned Friday that if the U.S. doesn’t "start seeing meaningful changes in the way Israel is prosecuting these [military] operations [in Gaza] and allowing for humanitarian assistance [in Gaza], and working toward a hostage deal and cease-fire, then we’re going to have to make changes in our Gaza policy."

In his interview with ABC News' "Good Morning America," Kirby would not say if those changes in Gaza policy would mean conditioning U.S. aid.

But Kirby said President Joe Biden was very clear on his call Thursday with Israeli Prime Minister Benjamin Netanyahu that the U.S. must "see some changes."

"We’ve got to see the humanitarian situation improve in Gaza, or otherwise we will have to try to take a look at our own policy and make decisions, and change the way that we’re supporting Israel," Kirby said.

3:07

White House official on how Israel must change conduct of Gaza war

The U.S. still wants an immediate cease-fire in exchange for the release of the Israeli hostages and for getting more aid into Gaza, Kirby stressed. U.S. officials will be among the negotiators meeting this weekend in Cairo, he said.

Israel Defense Forces released a statement Friday about the deadly airstrike in Gaza that killed seven World Central Kitchen aid workers on April 1.

The IDF said it misidentified a WCK worker in the convoy as a Hamas gunman.

"After the vehicles left the warehouse where the aid had been unloaded, one of the commanders mistakenly assumed that the gunmen were located inside the accompanying vehicles and that these were Hamas terrorists. The forces did not identify the vehicles in question as being associated with WCK," the IDF said in a statement Friday.

"Following a misidentification by the forces, the forces targeted the three WCK vehicles based on the misclassification of the event and misidentification of the vehicles as having Hamas operatives inside them, with the resulting strike leading to the deaths of seven innocent humanitarian aid workers," the statement continued.

The report said there were three strikes on the convoy. It also said WCK workers hit in the first vehicle were hit again while moving to another vehicle in the convoy.

"The investigation's findings indicate that the incident should not have occurred. Those who approved the strike were convinced that they were targeting armed Hamas operatives and not WCK employees," the IDF said. "The strike on the aid vehicles is a grave mistake stemming from a serious failure due to a mistaken identification, errors in decision-making, and an attack contrary to the Standard Operating Procedures."

It said WCK correctly coordinated its movements with the IDF prior to the night the workers were killed and that there was a "comprehensive plan" in place for the WCK movement on April 1.

U.S. Secretary of State Antony Blinken was asked about the announcement from Israeli Prime Minister Benjamin Netanyahu's office's announcement overnight that additional crossings into Gaza would be opened up for aid to enter.

He said the U.S. "welcomed" the development but that "the real test is results, and that's what we're looking to see in the coming days, the coming weeks."

"Is the aid effectively reaching the people who need it throughout Gaza?" he said. "Do we have a much better system for deconfliction and coordination so that the humanitarian workers, the folks who are delivering the aid, can do it safely and securely? All of these things are critical."

Blinken said these aims would be measured by clear metrics "like the number of trucks that are actually getting in on a sustained basis," and the aid making it to those in need through the enclave — "including critically northern Gaza."

He said the administration would be closely watching to see if other measurements were reversed, including "the fact that almost 100% of the population is acutely food insecure" as well as indicators of potential famine.

"So really, the proof is in the results," he said.

ABC News' Shannon Crawford

The partner of one of the seven World Central Kitchen aid workers killed in an Israeli air strike in Gaza this week is pleading for answers into the deadly attack.

"We need some answers," Sandy Leclerc, the partner of Jacob Flickinger, a dual U.S.-Canadian citizen, told ABC News on Thursday in her first television interview since the attack. "We need the truth of what happened because this situation is so unclear."

"Please Mr. Biden, give us the truth of what happened," she asked of President Joe Biden as she spoke with ABC News correspondent Phil Lipof.

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Partner of killed Canadian-U.S. aid worker asks Biden for answers

If Israel strikes back, the response speed from Iran "will be less than a few seconds," said Ali Bagheri Kani, the deputy foreign minister of Iran for political affairs.