The US Pentagon has outlined proposals to the White House that would send military reinforcements to the Middle East to beef up defences against Iran amid heightened tensions in the region.
President Donald Trump, speaking before the meeting, said he was not convinced more troops were needed but would do whatever was necessary.
Acting Defence Secretary Patrick Shanahan told reporters the Defence Department has not yet determined how many troops might be sent to reinforce the existing US military presence in the region.
He disputed reports the Pentagon was proposing to send up to 10,000 more troops to the Middle East, saying they were "not correct".
"What we're focused on right now is, do we have the right force protection in the Middle East," Shanahan said, referring to defensive forces.
He said he was in regular contact with Marine Gen. Kenneth F. McKenzie, the Central Command chief, about how to shape the US force presence in the Mideast with potential Iranian threats in mind.
Officials said the proposed troop reinforcements were not a response to any new threat from Iran but aimed at strengthening security for existing forces.
They said the troops would be defensive forces and discussions included additional Patriot missile batteries, more ships and increased monitoring.
Any move to deploy more forces would signal a shift for Trump, who has emphasised the need to reduce America's Mideast troop presence.
US officials have provided few details about possible Iranian threats but indicated they initially involved missiles loaded onto small Iranian boats. This week officials said the missiles have been taken off the boats near Iran's shore, but other maritime threats continue.
During back-to-back closed briefings for the House and Senate on Tuesday, defence leaders told congressional officials the US doesn't want to go to war with Iran and wants to de-escalate the situation.
Many in Congress are skeptical of the administration's approach to Iran, questioning whether it is responding to significant new Iranian threats or escalating a situation that could lead to war.
In early May, the U.S. accelerated the deployment of an aircraft carrier strike group to the Mideast and sent four B-52 bomber aircraft to the region.
The Pentagon also decided to move a Patriot air-defence missile battery to an undisclosed country in the area.
Some Democrats say Trump is responsible for drawing Iran's ire. Last year he abruptly pulled the US out of the Iran nuclear deal, negotiated during the Obama administration to prevent Iran from nuclear weapons production, without crafting a coherent strategy for how to combat other Iranian behaviour like supporting extremist organisations.
He also has reimposed punishing sanctions.
