The United States launched cruise missiles against an airbase in Syria on Thursday night in retaliation for this week's chemical weapons attack against civilians, which the U.S. and others say was carried out by Syrian President Bashar al-Assad. It was the first direct U.S. assault on the Syrian government and Donald Trump's most dramatic military order since becoming president.

Read a transcript of the statement Trump made shortly after the attack as well as other statements made by U.S. officials.

Statement by Donald Trump:

My fellow Americans: On Tuesday, Syrian dictator Bashar al-Assad launched a horrible chemical weapons attack on innocent civilians. Using a deadly nerve agent, Assad choked out the lives of helpless men, women, and children. It was a slow and brutal death for so many. Even beautiful babies were cruelly murdered in this very barbaric attack. No child of God should ever suffer such horror.

Tonight, I ordered a targeted military strike on the airfield in Syria from where the chemical attack was launched. It is in this vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons. There can be no dispute that Syria used banned chemical weapons, violated its obligations under the Chemical Weapons Convention, and ignored the urging of the UN Security Council.

US Syria

The guided-missile destroyer USS Porter (DDG 78) launches a Tomahawk land attack missile in the Mediterranean Sea - one of dozens launched against Syria Thursday evening by the U.S. (Mass Communication Specialist 3rd Class Ford Williams/U.S. Navy/Associated Press)

Years of previous attempts at changing Assad's behaviour have all failed, and failed very dramatically. As a result, the refugee crisis continues to deepen and the region continues to destabilize, threatening the United States and its allies.

Tonight, I call on all civilized nations to join us in seeking to end the slaughter and bloodshed in Syria, and also to end terrorism of all kinds and all types.  We ask for God's wisdom as we face the challenge of our very troubled world.  We pray for the lives of the wounded and for the souls of those who have passed.  And we hope that as long as America stands for justice, then peace and harmony will, in the end, prevail.

Goodnight. And God bless America and the entire world. Thank you.

Statement by U.S. Secretary of State Rex Tillerson:

It's also important to recognize, as I think everyone does, the chaotic circumstances that exist on the ground in Syria with the presence of a battle underway to defeat ISIS, the presence of al-Qaeda elements inside of Syria and a civil war that is underway. Clearly one of the existential threats we see on the ground in Syria, is if there are weapons of this nature available in Syria, the ability to secure those weapons and not have them fall into the hands of those who would bring the weapons to our shores to harm American citizens.

So there are a number of elements that in our view that called for this action tonight, which we feel is appropriate. We feel that the strike itself was proportional because it was targeted at the facility that delivered this most recent chemical weapons attack.

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U.S. Secretary of State Rex Tillerson was in Palm Beach, Fla., Thursday, where he and Trump were meeting with Chinese President Xi Jinping. (Joe Skipper/Reuters)

We co-ordinated very carefully with our international partners in terms of communicating with them around the world. I would tell you that the response from our allies, as well as the region and the Middle East has been overwhelmingly supportive of the action we taken.…

This was a very deliberative process. There was a thorough examination of a wide range of options, and I think the president made the correct choice and made the correct decision. First, to be decisive in acting, acting against this heinous act on the part of Bashar Assad, but acting in a way that was clearly directed at the source of this particular attack to send that strong message.

Other things were considered. Those were rejected for any number of reasons. In my view, the president made the exact, correct decision. 

Statement by U.S. National Security Adviser H.R. McMaster:

It was important during the president's deliberations and in deliberations with his leadership that we weighed the risk associated with any military action, but we weighed that against the risk of inaction, which Secretary Tillerson has already really summarized, which is the risk of this continued, egregious, inhumane attacks on innocent civilians with chemical weapons. 

The president was immediately notified upon news of the chemical attack. He was very interested in understanding better the circumstances of the attack and who was responsible.

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Trump's National Security Adviser, Lt. Gen. H.R. McMaster, said there were three options discussed with the president before he opted for the missile attack. (Kevin Lamarque/Reuters)

That confidence level has just continued to grow in the hours and days since the attack associated with additional evidence, especially with so sad, sadly, with the victims that are being treated and confirmation of the type of agent which was used, which is a nerve agent.

We convened a meeting of the National Security Council ... to deliberate on options.

There were three options we discussed with the president, and the president asked us to focus on two options in particular, to mature those options, and he had a series of questions for us that we endeavoured to answer.

We were able to answer those questions and come back to him in a decision briefing today with virtually all of the principals of the National Security Council here in Florida and by video teleconference back in Washington.

After a meeting of considerable length and a far-reaching discussion, the president decided to act and that's the general sequence of events.

So, two rather large and formal meetings, but really a whole series of discussions since the time of the attacks.

Statement by U.S. Pentagon:

At the direction of the president, U.S. forces conducted a cruise missile strike against a Syrian Air Force airfield today at about 8:40 p.m. ET (4:40 a.m. on Friday in Syria). The strike targeted Shayrat Airfield in Homs governorate, and were in response to the Syrian government's chemical weapons attack April 4 in Khan Sheikhoun, which killed and injured hundreds of innocent Syrian people, including women and children.

The strike was conducted using Tomahawk Land Attack Missiles (TLAMs) launched from the destroyers USS Porter and USS Ross in the Eastern Mediterranean Sea. A total of 59 TLAMs targeted aircraft, hardened aircraft shelters, petroleum and logistical storage, ammunition supply bunkers, air defence systems, and radars. As always, the U.S. took extraordinary measures to avoid civilian casualties and to comply with the Law of Armed Conflict. Every precaution was taken to execute this strike with minimal risk to personnel at the airfield.

The strike was a proportional response to Assad's heinous act. Shayrat Airfield was used to store chemical weapons and Syrian air forces.  The U.S. intelligence community assesses that aircraft from Shayrat conducted the chemical weapons attack on April 4.  The strike was intended to deter the regime from using chemical weapons again.

Russian forces were notified in advance of the strike using the established deconfliction line. U.S. military planners took precautions to minimize risk to Russian or Syrian personnel located at the airfield.

We are assessing the results of the strike. Initial indications are that this strike has severely damaged or destroyed Syrian aircraft and support infrastructure and equipment at Shayrat Airfield, reducing the Syrian Government's ability to deliver chemical weapons. The use of chemical weapons against innocent people will not be tolerated.

Shayrat military airbase

The airstrike early Friday local time in Syria targeted the Shayrat military airbase in Homs. (CBC)