The US said Israel acted "unilaterally," though President Donald Trump warned of more "brutal" Israeli attacks to come.

The secretary of defense also defended cuts to the E-7 Wedgetail, Constellation-class frigate, and Ukraine assistance funds during the congressional hearing.

The investment comes as among the first in a bid to reach an ambition of manufacturing one SSN every 18 months, which are set to be delivered from the end of the 2030s.