US has yet to lay blame for device attacks across Lebanon. Why?

Deadly device blasts across Lebanon this week broadly believed to have been orchestrated by Israel have sparked concern and even outright condemnation from much of the international community, putting the Biden administration in a delicate position as it seeks to avoid a broader war in the Middle East.

More than 48 hours have passed since electronic devices -- pagers and walkie-talkies -- distributed to members of the U.S.-designated terrorist group Hezbollah began exploding en masse, killing at least 37 people and wounding 2,931 others, Lebanese officials said. But the Biden administration has yet to attribute responsibility for the operation or forcefully denounce the collateral damage it caused, which Lebanese authorities say includes the deaths of at least two children.

When asked during a press briefing Thursday whether the act might constitute terrorism, White House press secretary Karine Jean-Pierre said she wouldn't weigh in from the podium but acknowledged "obviously children being harmed, people being harmed is difficult to see and not something that we want to see."

State Department spokesperson Matthew Miller also declined to comment on whether the attacks were a legitimate form of warfare, but said that "as a general principle, we do believe it's a legitimate practice for any country to defend itself by fighting terrorist organizations."

However, sources tell ABC News the CIA has long been reluctant to use the strategy employed in the operation, which relies on infiltrating supply chains, because of the high risk to innocents.

Global organizations, including the United Nations, have issued clear condemnations of the attacks, which took place on Tuesday and Wednesday.

"Simultaneous targeting of thousands of individuals, whether civilians or members of armed groups, without knowledge as to who was in possession of the targeted devices, their location and their surroundings at the time of the attack violates international human rights law," the United Nations High Commissioner for Human Rights said in a statement.

The U.N. has called for a full investigation into the matter, and the body's Security Council is also set to hold an emergency meeting on Friday to discuss the attacks.

But experts on humanitarian law and military strategy say it's not evident the attacks violate international standards.

"It's a whole lot more targeted than dropping a 2,000-pound bomb," said Raphael Cohen, a senior political scientist at Rand Corp. "This was about as good as you can get from a mitigation standpoint."

"My experience tells me it's proportional," retired Col. Seth Krummich, former chief of staff for special operations of U.S. Central Command and the vice president of Global Guardian, an international security services provider, said of the attacks. "This is an operational and tactical level success for Israel."

Israel has not taken credit for the mass explosions, but in the aftermath of a second round of explosions in Lebanon, Prime Minister Benjamin Netanyahu implied that his government would do whatever it deemed necessary to put a stop to the near-continuous rocket volleys fired by Hezbollah that have displaced thousands of Israelis living along the border with Lebanon.

"I have already said we will return the residents of the north safely to their homes," Netanyhau said. "And that's exactly what we'll do."

A U.S. intelligence source confirmed to ABC News on Thursday that Israel had a hand in the manufacturing of the pagers that exploded this week, with this type of "supply chain interdiction" operation having been planned for at least 15 years.

Biden administration officials have feverishly worked to avoid escalation between Hezbollah and Israel since Hamas carried out the Oct. 7 attacks out of concern that an intensified conflict between the two would spiral into a destabilizing regional war.

The U.S. and Israel haven't always been aligned when it comes to best practices for countering Hezbollah, but the Biden administration's chief concern now is limiting the potential for escalation, and it sees minimizing public disagreement with Israel as beneficial toward that aim, according to officials familiar with the matter.

But de-escalation continues to be a fleeting target for the U.S., and experts are divided on whether the attacks might have weakened Hezbollah to the extent it's more willing to accept a diplomatic agreement, or if the group will indeed act on its threat to retaliate.

"Oftentimes, shows of force like this that knock one combatant back on its heels could be openings to actually secure a negotiated settlement," said Brian Katulis, a senior fellow at the Middle East Institute who has worked with the National Security Council as well as departments of State and Defense.

Katulis said although Hezbollah has likely maintained the capacity to launch its own reprisal, the group may not be able to defend itself from Israel's ensuing retribution.

"Their command-and-control ability to coordinate in response to an Israeli retaliation is probably severely weakened," he said.

Israel on Thursday launched a series of strikes on Hezbollah targets, saying it carried out hundreds of strikes in Lebanon. Earlier, Israel said it hit at least 30 Hezbollah targets in southern Lebanon, including a weapons storage facility, adding it will continue to "operate against the threat of the Hezbollah."

Others, such as Dan Byman -- a senior adviser to the State Department and a senior fellow at the Center for Strategic and International Studies -- said although Hezbollah has endured a significant setback, the group is now far less likely to take any offered settlement.

"It would be hard for Hezbollah to cut a deal after this humiliation, that it would look weak and as if you were caving under Israeli pressure. Which it would be," Byman said.