The US is sending a small number of additional troops to the Middle East due to escalating tensions between Israel and Hezbollah, the Pentagon said on Monday, declining to specify the precise number or mission of the deployed forces.

“Out of an abundance of caution, we are sending a small number of additional US military personnel forward to augment our forces that are already in the region,” air force Maj Gen Patrick Ryder, a Pentagon spokesperson, told reporters.

“We have more capability in the region today than we did on April 14th when Iran conducted its drone and missile attack against Israel,” Ryder said, referring to Iran’s attack by more than 300 missiles and drones, which caused only modest damage inside Israel thanks to air defence interceptions from the United States, Britain and other allies in the region.

“So all of those forces combined provide us with the options to be able to protect our forces should they be attacked.”

The US capabilities in the region include the Abraham Lincoln aircraft carrier strike group, fighter aircraft and air defences.

The IDF has said it launched a fresh wave of strikes on Lebanon overnight, targeting positions from which rockets were fired towards Israel.

In an update online, IDF officials said that “warplanes targeted dozens of sites” in several areas in southern Lebanon.

The statement said that secondary explosions were observed during the strikes “indicating the presence of weapons stored in the buildings.” The Guardian was unable to verify this.

Monday saw some of the heaviest cross-border fire exchange in almost a year. Israel says it has started shifting its focus north to Hezbollah, which has been firing rockets into Israel in support of Hamas.

Hello and welcome to the Guardian’s continuing coverage of the crisis in the Middle East.

Israel has said it launched a fresh wave of strikes on Hezbollah overnight, targeting positions that had fired rockets into Israel. The IDF said it had attacked “dozens of targets” in several areas in southern Lebanon.

The announcement comes a day after 492 people were killed in Lebanon by Israeli airstrikes. Almost 1,650 people were injured as well, according to the Lebanese health ministry.

Benjamin Netanyahu, the Israeli prime minister, said the military was changing the “security balance” along its northern border.

Tens of thousands of people fled from south Lebanese towns and villages along the main road towards the capital, Beirut, in Israel’s most intense barrage in nearly a year of cross-border clashes, as sirens were also heard in the northern Israeli city of Haifa. The Lebanese health ministry said 35 children and 58 women were among those killed.

More on that in a moment, first here’s a summary of the day’s other main events.

• Israeli defence minister Yoav Gallant said Israel’s airstrikes in Lebanon on Monday destroyed tens of thousands of Hezbollah rockets. The Israeli military is preparing for the next stage of its operation in Lebanon after launching a wave of airstrikes against Hezbollah targets on Monday morning, the military chief of the general staff Herzi Halevi said. There is rising tension on the ground in Lebanon and a collective bracing to see whether Israel intends a ground invasion of its neighbour.

• Nasser Yassin, the Lebanese minister coordinating the crisis response, told Reuters 89 temporary shelters in schools and other facilities had been activated, with capacity for more than 26,000 people. Families from south Lebanon loaded cars, vans and trucks with belongings and people, sometimes multiple generations in one vehicle. As bombs rained down, children crammed on to parents’ laps and suitcases were tied to car roofs. Highways north were gridlocked.

• The United States does not think Israeli escalation to force Hezbollah to reduce tensions will yield the desired outcome of de-escalation, a senior State Dept official said on Monday, effectively disagreeing with Israel’s strategy. The conflict is a key focus for secretary of state Antony Blinken on the sidelines of the UN general assembly this week, where Washington had concrete ideas to prevent a broader war and would seek an “off ramp” to the tensions, the official told reporters in New York.

• The United Nations peacekeeping force in Lebanon (Unifil) issued a statement on Monday afternoon expressing “grave concern” for the safety of civilians in southern Lebanon amid the most intense Israeli bombing campaign since last October and urging the need for de-escalation from both Hezbollah and Israel.

• Najib Mikati, Lebanon’s caretaker prime minister, has called Israel’s wave of airstrikes “a genocide in every sense of the word”. Mikati made the comments at the start of a cabinet meeting in Beirut on Monday in which he said that Israel’s airstrikes aim to destroy Lebanon’s towns and villages, according to an update from the Associated Press news agency. Mikati said that the Lebanese government was calling on the United Nations, the UN security council and world nations to “deter the aggression”.

• France has requested an emergency UN security council meeting to discuss Lebanon. “I have requested that an emergency meeting of the Security Council be held on Lebanon this week,” French foreign minister Jean-Noel Barrot told the UN general assembly on Monday, calling on all sides to “avoid a regional conflagration that would be devastating for everyone.”.