BRUSSELS (Reuters) - The European Union said on Friday it understood the aim of U.S. missile strikes in Syria as an effort to deter any more chemical attacks there, but highlighted political solutions as the only way to end the war.

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The nuanced line taken by the bloc’s 28 states reflects their disgust at a chemical attack that killed scores of people in a rebel-held area this week, but also a worry about any more escalation in the conflict following the unilateral U.S. move.

“The U.S. has informed the European Union that ... (it) launched a strike on Shayrat Airfield in Syria with the understandable intention to prevent and deter the spread and use of deadly chemical weapons,” the bloc’s top diplomat, Federica Mogherini, said in a statement on behalf of all member states.

“The U.S. also informed us that these strikes are limited and focused on preventing and deterring further use of chemical weapons atrocities,” the statement read.

She added that the use of chemical weapons was a war crime and perpetrators of such acts “should be sanctioned within the framework of the United Nations.”

The bloc supports Syrian opposition rebels and some moderate rebels negotiating under U.N.-mediated talks with representatives of Damascus. The talks have long been stalled and the war, which is in its seventh year, has killed more than 400,000 people and sent millions from their homes.

“The EU firmly believes that there can be no military solution to the conflict,” the joint statement said. “Only a credible political solution... will ensure peace and stability.”

While France and Britain have led calls for Syrian President Bashar al-Assad to go, some other EU states, including the Czech Republic, Hungary, Spain and Italy, are more dovish.

But the bloc’s role in international peace efforts has been largely marginal as it lacks influence on the ground, where Russia’s military intervention has given Assad the upper hand.

The EU is the largest aid donor in Syria, and has threatened it will not pay for reconstruction of the country if Assad and his allies take full control by wiping out the opposition.

The EU says a “credible political transition” must start first with the aim of giving the opposition and Syria’s various ethnic and religious groups political representation.

The chairman of EU leaders Donald Tusk, French Foreign Minister Jean-Marc Ayrault, the Polish foreign ministry as well as a British government spokesman supported Washington.

“U.S. strikes show needed resolve against barbaric chemical attacks. EU will work with the US to end brutality in Syria,” Tusk said on Twitter.

But German Foreign Minister Sigmar Gabriel, Belgium’s Didier Reynders and the head of the EU’s executive arm stuck to a more cautious line, saying they “understood” the aim of the strikes, but highlighting more strongly the need for a negotiated end to the war.

“There is a clear distinction between air strikes on military targets and the use of chemical weapons against civilians,” said the head of the European Commission, Jean-Claude Juncker.

“Efforts to stem the spiral of violence in Syria and work toward a lasting peace should be redoubled. Only a political transition can lead to such an outcome.”