No one was injured, according to the Qatari Ministry of Defense.
President Donald Trump announced "major combat operations" against Iran on Saturday, with daytime strikes in the joint U.S.-Israel attack targeting military and government sites, officials said.
On Sunday, Iranian state television confirmed that Ayatollah Ali Khamenei was among those killed by airstrikes in Tehran on Saturday.
Iran is responding to the U.S.-Israeli operation with missile and drone attacks targeting Israel, regional U.S. bases and Gulf nations. American diplomatic facilities have also been attacked.
In Lebanon, Israel is intensifying its long-running strike campaign against the Iranian-aligned Hezbollah militia.
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The U.S. embassy in Amman, Jordan, announced it is canceling appointments until further notice and has instructed personnel to shelter-in-place.
"The embassy has instructed all Mission personnel to shelter-in-place. We recommend all Americans do the same," the alert on Wednesday said.
Canadian Prime Minister Mark Carney told reporters the U.S. and Israel's actions in Iran may be "inconsistent with international law."
"It's for the United States and Israel to make the case, and whether or not that is the case," he said. "It is for others more expert than me -- I'm not a lawyer, certainly not an international lawyer -- who are more expert to make that determination."
Carney said Canada regrettably supports efforts to prevent Iran from obtaining a nuclear weapon "because the current conflict is another example of the failure of the international order."
"Despite decades of United Nations Security Council resolutions, the tireless work of the International Atomic Energy Agency, and a succession of sanctions and diplomatic frameworks, Iran’s nuclear threat remains," Carney said. "And now the United States and Israel have acted without engaging the United Nations or consulting with allies, including Canada."
Carney called for a "rapid de-escalation of hostilities."
"Resolution of this crisis requires commitment to a broader political solution," he said. "Diplomatic engagement is essential to avoid a wider and deeper conflict."
The Al Udeid Air Base -- the largest US military base in the Middle East -- was struck by a ballistic missile from Iran, the Qatari Ministry of Defense said early Wednesday local time.
No one was injured, it said.
A second ballistic missile launched from Iran was intercepted, the defense ministry said.
Secretary of State Marco Rubio said the "intensity" of the U.S.-Israeli attacks on Iran will ramp up in the coming hours and days.
"You're going to really begin to perceive a change in the scope and the intensity of these attacks as, frankly, the two most powerful air forces in the world take apart this terroristic regime and defang it and take away its ability to threaten its neighbors or hide behind the zone of immunity that allows them to develop nuclear ambitions," Rubio told reporters earlier Tuesday.
