US, French and British missiles destroyed suspected chemical weapons development and storage sites in Syria on Saturday in response to an alleged chemical attack in the town of Douma which killed at least 40 people.

The 28 ministers condemned the military offensive, backed by Russia, that the Syrian government is waging against rebels and called for an immediate ceasefire to allow humanitarian access.

EU foreign ministers on Monday backed "all efforts" to stop Syria using chemical weapons, after weekend strikes by Britain, France and the US, but called for renewed efforts to find a political solution to the seven-year war.

"The Council understands that the targeted US, French and UK airstrikes on chemical weapons facilities in Syria were specific measures... with the sole objective to prevent further use of chemical weapons and chemical substances as weapons by the Syrian regime to kill its own people," the statement said.

"The Council is supportive of all efforts aimed at the prevention of the use of chemical weapons."

French Foreign Minister Jean-Yves Le Drian said the EU was "united at a very serious moment" in wanting to "prevent and dissuade against any use of chemical weapons".

Germany's powerful Chancellor Angela Merkel declared the strikes "necessary and appropriate", but other EU members have been keen to avoid any step that could lead to further escalation.

Johnson stressed the strikes were "not an attempt to change the tide of the war in Syria or to have regime change or to get rid of Bashar al-Assad".

The day before the strikes Russian President Vladimir Putin warned during phone talks with his French counterpart Emmanuel Macron against "ill-considered and dangerous actions" in Syria which could lead to "unpredictable consequences".

Russian role

Ministers discussed ways to apply pressure to get Russia to drag the Assad government to meaningful negotiations on the future of his country.

"You have to see it, whether you like it or not: without Russia you won't be able to solve this conflict," German Foreign Minister Heiko Maas said as he arrived for Monday's talks.

Washington has said it will impose new sanctions on Russia over the Douma attack, targeting companies that supplied Syria with equipment related to chemical weapons, but the EU is not yet ready to follow suit.

Missiles destroyed suspected chemical weapons development and storage sites in Syria on Saturday in response to an alleged chemical attack in the town of Douma which killed at least 40 people (photo by: Handout/Cnes 2017, Distribution Airbus DS/AFP/File)

An EU dipl

omat told AFP that it would be possible to add Russians or Iranians to the Syrian sanctions list, but the idea is not yet being discussed at the level of foreign ministers.

Some European governments are wary of provoking an angry response from Russia, which among other things remains a key supplier of gas to the EU.

Moscow has been keen to exploit fissures within the EU that were laid bare by the response to the poisoning of former Russian spy Sergei Skripal and his daughter in England.

All 28 EU leaders signed up to a statement blaming Russia for the poisoning at a summit in Brussels last month, but only after intense lobbying by Britain, France and Germany.

Afterwards, 18 EU countries followed Britain's lead and expelled Russian diplomats from their territory, six took the more limited step of recalling their own ambassadors, and three did nothing.

'No military solution'

Next week the EU hosts a major conference in Brussels on the future of Syria aimed at gathering financial pledges for humanitarian aid and boosting a floundering UN-led peace process.

In their statement ministers said "the momentum of the current situation should be used to reinvigorate the process to find a political resolution of the Syrian conflict".

Foreign Minister Nicos Christodoulides attend an EU foreign affairs council in Luxembourg (photo by: Emmanuel DUNAND/AFP)

The EU insists "there can be no military solution" to the war in Syria, which has killed over 350,000 people, and has repeatedly called for the UN-led talks in Geneva to be given fresh impetus.

But privately some European diplomats already acknowledge that the Assad regime's military campaign is likely to succeed and they should begin planning for the next stage.