Iran live updates: White House calls on other nations to secure Strait of Hormuz

The U.S.-Israeli strikes on Iran are not part of an "endless nation-building" effort, Defense Secretary Pete Hegseth said on Tuesday.

"This is not 2003. This is not endless nation building under those types of quagmires we saw under Bush or Obama," Hegseth said during a Pentagon press briefing. "It's not even close. Our generation of soldier will not let that happen again."

Hegseth added that President Donald Trump would not allow such open-ended conflict, saying he "very clearly ran against those kinds of never ending nebulously scoped missions. Those days are dead."

Secretary of Defense Pete Hegseth said on Tuesday that U.S. strikes on Tehran would continue to amplify, meaning Tuesday's aerial strikes would mark "the most intense" of the 10-day conflict.

"Iran stands alone and they are badly losing on day 10 of Operation Epic Fury," Hegseth said. "We are winning with an overwhelming and unrelenting focus on our objectives, which are the same as the day I gave my first briefing here on Operation Epic Fury."

Defense Secretary Pete Hegseth and Gen. Dan Caine, chairman of the Joint Chiefs of Staff, are scheduled to hold a press conference at 8 a.m. ET on Tuesday, according to the Department of Defense.

Nearly 40 people were killed in a strike on two buildings in eastern Tehran, according to local authorities, as the semi-official Tasnim News Agency reported Monday evening.

Two buildings, each containing 20 residential flats, were destroyed by missiles, the semi-official Mehr News Agency reported, quoting the head of the Tehran Fire Department.

"Tens of martyrs have been taken out. Many bodies are still under the rubble, and one body recovered from the building cannot be identified as a woman or a man because it is totally disintegrated," the head of the Tehran Fire Department said, according to Mehr.

-ABC News' Somayeh Malekian