The US has sent a guided missile submarine to the Middle East, as tensions grow in the region.
Defence Secretary Lloyd Austin also said an aircraft carrier that was already heading to the area would sail there more quickly.
It signals the US’s determination to help defend Israel from any attack by Iran – with Mr Austin saying US would “take every possible step” to defend its ally.
In a statement on Sunday, the Pentagon said Mr Austin had sent the the USS Georgia guided missile submarine to the region. The submarine can carry up to 154 Tomahawk cruise missiles, which are used to strike land targets.
It had also ordered the USS Abraham Lincoln carrier strike group, which is carrying F-35C fighter jets, to accelerate its journey there. The ship was already on its way to replace another US ship in the region.
The move comes in response to fears of a wider regional conflict, after the recent assassination of senior Hezbollah and Hamas leaders.
Iran is being closely watched for any indication of how and when it might respond to the assassination of Hamas’s top political leader Ismail Haniyeh in Tehran on 31 July.
The Iranians blamed Israel for the assassination of Mr Haniyeh on their soil, and have vowed to punish it. Israel has not commented but is widely believed to have been behind it.
It remains unclear what Iran could be planning to do.
Meanwhile, another possible attack on Israel could come from Hezbollah, the Iranian-backed militia and political movement in Lebanon.
The group has vowed to respond to the killing by Israel of senior commander Fuad Shukr, which happened just hours before Mr Haniyeh’s assassination, in Beirut’s southern suburbs.
