Here are the latest developments.

American stealth bombers struck weapon facilities overnight in areas of Yemen controlled by the Iran-backed Houthi militia, an attack that could serve as a warning to Tehran.

The attack underscored the importance of U.S. military backup to Israel even as Washington warned that the support could be cut off if more were not done to ease a humanitarian crisis in northern Gaza.

The strikes in Yemen on Wednesday targeted five Houthi weapon caches. They followed the U.S. deployment to Israel this month of an advanced missile defense system — and the 100 troops needed to operate it — after an Iranian missile attack on Oct. 1.

The United States and other countries have also heaped pressure on Israel to address the escalating humanitarian crisis that threatens hundreds of thousands of people in northern Gaza. This week, Defense Secretary Lloyd J. Austin III and Secretary of State Antony J. Blinken warned Israel that the United States could cut off military assistance if humanitarian aid were not allowed to enter northern Gaza, where Israel says it is conducting strikes on Hamas.

And in a rare moment of unity, every member of the United Nations Security Council on Wednesday agreed that Israel must consistently allow aid into northern Gaza, where an estimated 400,000 people have been trapped by fighting, and must drastically scale up assistance to the rest of the enclave.

On Thursday, the Israeli forces pressed on with their military operations in northern Gaza. An Israeli strike on a school building killed more than 20 people, according to the Palestinian Civil Defense, an emergency service. Israel’s military said that it had attacked the site, in Jabaliya, because dozens of Hamas and Islamic Jihad militants had been meeting there at the time.

Here’s what else to know:

• Polio vaccinations: The World Health Organization said that the second phase of its polio vaccination campaign in the Gaza Strip concluded on Wednesday, with 181,429 children vaccinated. Eight health facilities in the enclave will continue to provide polio vaccines for families the campaign has been unable to reach, the W.H.O. said.

• Israeli strikes: Israel’s military carried out airstrikes on Wednesday in Hezbollah-dominated areas of southern Lebanon and outside Beirut. They came after the Biden administration said that it had expressed concerns about the scale of Israel’s weekslong bombardment of Beirut, the Lebanese capital. The strikes in southern Lebanon hit municipal buildings in Nabatieh, killing at least 16 people, including the city’s mayor, and wounding more than 50, Lebanese officials said.

• Medical evacuations: The Israeli military said that it allowed one person to leave Gaza for medical treatment in Jordan on Wednesday, one day after the Israeli Supreme Court on Tuesday ordered the government to explain why there appeared to be no comprehensive system to facilitate evacuations of sick civilians from the enclave.