German Chancellor Angela Merkel called the military intervention "necessary and appropriate" | Michele Tantussi/AFP via Getty Images Broad support from EU leaders for Syria strikes German Chancellor Angela Merkel said the strikes were “necessary and appropriate.”

European leaders on Saturday expressed wide support for overnight strikes against the Syrian regime by the U.S., U.K. and France, with German Chancellor Angela Merkel calling the intervention "necessary and appropriate."

The action — in response to a suspected chemical weapons attack on civilians in the city of Douma — is the biggest military Western intervention into the country’s seven year civil war.

It involved strikes on three Syrian regime facilities that the three powers said would degrade the capability of Bashar al-Assad's forces to use chemical weapons.

German Chancellor Angela Merkel said the military intervention was "necessary and appropriate, to ensure the effectiveness of the international ban of chemical weapons use and to warn the Syrian regime of further violations."

Merkel also accused Russia of repeatedly blocking an independent investigation in the U.N., saying all evidence pointed to the Syrian regime as responsible for the recent chemical attack.

“The use of chemical weapons is unacceptable" — Antonio Tajani

On Thursday, she said Germany would not participate in any strike, expressing support that "everything is done to send a signal that this use of chemical weapons is not acceptable.”

Merkel's comments were echoed by Spain, with Foreign Minister Alfonso Dastis who tweeted Saturday that, "The use of #chemicalweapons is a crime against humanity, nothing can justify it. The strikes carried out in #Syria by the US, France and the UK are legitimate and proportionate."

European Commission President Jean-Claude Juncker said in a statement that the "use of chemical weapons is unacceptable in any circumstances and must be condemned in the strongest terms. The international community has the responsibility to identify and hold accountable those responsible of any attack with chemical weapons."

Strikes by US, France and UK make it clear that Syrian regime together with Russia & Iran cannot continue this human tragedy, at least not without cost. The EU will stand with our allies on the side of justice. — Donald Tusk (@eucopresident) 14 april 2018

Donald Tusk, the President of the European Council, tweeted that the strikes "make it clear that [the] Syrian regime together with Russia [and] Iran cannot continue this human tragedy, at least not without cost. The EU will stand with our allies on the side of justice."

The European Union’s foreign policy chief Federica Mogherini said in a statement Saturday that the EU “is supportive of all efforts aimed at the prevention of the use of chemical weapons.

"The use of chemical weapons or chemical substances as weapons is a war crime and a crime against humanity,” she said, adding that "perpetrators will be held accountable for this violation of international law.”

The EU imposed additional sanctions on high-level officials and scientists for their role in developing and using chemical weapons in July 2017 and last month, Mogherini said, warning the bloc "is always ready to consider imposing further measures as appropriate.” A conference on Syria which will take place in Brussels later this month and is co-chaired by the EU and the U.N., is meant to relaunch support for finding a political solution to the conflict, she said.

Antonio Tajani, the president of the European Parliament, said the assembly will hold a plenary debate on the strikes on Monday in Strasbourg.

"The use of chemical weapons is unacceptable. Europe must play a greater role in securing peace and preventing the aggravation of humanitarian crises like the suffering of the Syrian people," he said on twitter.

NATO Secretary-General Jens Stoltenberg also welcomed the attack, saying it "will reduce the regime’s ability to further attack the people of Syria with chemical weapons."

Chemical weapons are a "threat to international peace and security," he said, adding that protecting the Chemical Weapons Convention "calls for a collective and effective response by the international community." NATO ambassadors are being briefed on the action in Brussels Saturday.

Russian President Vladimir Putin on Saturday, meanwhile, called the intervention an “act of aggression” that will exacerbate humanitarian catastrophe in Syria, according to Tass.

His envoy in Washington D.C. went a step further, and threatened retaliation. In a statement, he said that Moscow "warned that such actions will not be left without consequences. All responsibility for them rests with Washington, London and Paris."

Wolfgang Ischinger, the chairman of the Munich Security Conference and a former German ambassador to Washington D.C., questioned whether the strikes were part of a long-term strategy in Syria.

Earlier this week, Ischinger tweeted that, "Merkel is right in not participating because isolated strikes are no substitute for a failed Syria policy. But not participating is also no substitute for a coherent Syria policy,” and called on EU leaders — especially, Paris, Berlin and the U.K. — to come up with an EU Syria strategy.