Senior administration officials said Secretary of State Mike Pompeo, national security adviser John Bolton and CIA Director Gina Haspel had favoured a military response.
The White House separately said it was aware of reports of a missile strike on Saudi Arabia amid a campaign targeting the kingdom by Yemen's Iranian-allied Houthi rebels.
Iran has said its Revolutionary Guard had shot down a USA drone flying over Iranian territory, days after the US accused Iran of shooting down a drone that was flying to the Gulf of Oman following reports of attacks on two tankers.
Earlier in the day, Trump had chosen not to reveal how the USA would respond to the downing of the drone, instead telling reporters "you'll find out".
Crude oil prices rose more than six percent after the incident which marked a new peak in tensions as Tehran pushes back against surging U.S. diplomatic, economic and military pressure. "I find it hard to believe it was intentional". "I think it could have been somebody who was loose and stupid that did it".
US President Donald Trump will be meeting later on Thursday with senior Pentagon officials to determine the nature of the response against Iran. Thursday's incident comes on the heels of a disputed attack on a pair of oil tankers in the Gulf of Oman last week.
It came days after the Pentagon accused Iran of attempting to shoot down a USA military drone as it was flying over one of the two crippled tankers, but without success. Tehran denies any involvement.
Tensions have been running high between Iran and the United States ever since President Donald Trump abandoned a landmark 2015 nuclear agreement in May previous year. "The risk to USA civil aviation is demonstrated by the Iranian surface-to-air missile shoot-down of a US unmanned aircraft system on 19 June 2019 while it was operating in the vicinity of civil air routes above the Gulf of Oman".
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The hit on Riviera Beach is the latest in a series of worldwide attacks aimed at extorting money from governments and businesses. Atlanta estimated that recovering from a sustained attack that debilitated the city a year ago could cost $17 million.
But the story gets more complicated, because in the last few weeks, Trump has sent mixed messages regarding his true intentions.
House Speaker Nancy Pelosi said no specific options for a U.S. response were presented at the more than hour-long meeting.
"We don't seek war, but will zealously defend our skies, land and waters", Mr Zarif said.
Subsequent reimposition of U.S. sanctions has badly hurt Iran's struggling economy.
In a speech on Iranian state TV, IRGC commander-in-chief Maj-Gen Hossein Salami said the drone's downing was a "clear message" to the USA that Iran's borders were "our red line".
The drone left a corkscrew smoke trail as it fell tens of thousands of feet into the sea after being hit by an Iranian missile, a direct attack by Iran on a USA military aircraft.
Thursday's drone incident marks the first direct Iranian-claimed attack on the United States amid the crisis. The U.S. military's central command characterized the incident as an "unprovoked attack".
Nor will the president make a nuclear deal with the regime, Graham said.