LUXEMBOURG (Reuters) - European Union foreign ministers on Monday threatened new sanctions against Syria over its alleged chemical attacks, but held off from joining expected new punitive U.S. measures against Russia.

Danish Foreign Minister Anders Samuelsen and French Minister for Foreign Affairs Jean-Yves Le Drian talk with Britain's Foreign Secretary Boris Johnson, European commissioner Johannes Hahn and Austrian Foreign Minister Karin Kneissl during European Union foreign ministers meeting in Luxembourg, April 16, 2018. REUTERS/Eric Vidal

After Britain and France joined the United States in missile salvoes meant to knock out Syrian chemical arms facilities, EU foreign ministers discussed steps to deepen the isolation of Syrian President Bashar al-Assad.

“The European Union will continue to consider further restrictive measures against Syria as long as the repression continues,” all 28 foreign ministers said in a statement after their talks in Luxembourg, referring to economic sanctions.

France’s Foreign Minister Jean-Yves Le Drian and his British counterpart Boris Johnson earlier briefed fellow ministers on the air strikes on Saturday. Le Drian said their endorsement showed European unity, after years of EU divisions over how best to end Syria’s seven-year-old war and whether Assad should be a part of any future government.

Western powers said the strikes were a response to an April 7 poison gas attack on the rebel enclave of Douma and were seen as a way to stop the use of chemical weapons.

“It is very important to stress (the strikes are) not an attempt to change the tide of the war in Syria or to have a regime change,” Johnson told reporters.

“I’m afraid the Syrian war will go on in its horrible, miserable way. But it was the world saying that we’ve had enough of the use of chemical weapons.”

Any new sanctions on Assad would build on a series of such EU measures since 2011, which range from an arms embargo and a ban on dealings with the Syrian central bank to travel bans and asset freezes on Syrian officials, military, business people and scientists accused of developing chemical weapons.

In a separate session, ministers discussed Iran’s role in Syria’s war, but there was no breakthrough on whether to adopt new sanctions proposed by Britain, France and Germany on Iranians accused of helping the Syrian regime.

EU diplomats said there was no discussion on Monday of targeting Russian military figures who, along with Iran, have helped Assad recapture rebel-held territory and are accused by the West of war crimes through aerial bombardments and gas attacks on civilians and hospitals.

CALL FOR AID ACCESS

The United States is considering new economic sanctions on Russia aimed at companies it alleges have dealt with equipment related to chemical weapons, according to U.S. ambassador to the United Nations, Nikki Haley.

EU diplomats cautioned that until European governments had more idea of what the United States was planning, it was not possible to quickly follow suit. In the past, EU measures have sometimes come months after Washington’s.

Russia is Europe’s biggest gas supplier and, while the EU has imposed significant sanctions on Moscow’s financial, energy and defence sectors over the crisis in Ukraine, close ties between Russia and some EU members complicate discussions about new punitive measures.

The foreign ministers, in their statement, singled out Russia and Iran, as well as Turkey, for blame in Syria, calling for an end to the war and humanitarian access to all besieged areas, saying 13.1 million people were in need of assistance.

“We have to keep pushing to get a ceasefire and humanitarian aid through the (United Nations) Security Council and eventually a peace process,” Dutch Foreign Minister Stef Blok told reporters in Luxembourg.

“The only solution is a peace process through the Security Council,” said Blok, who met his Russian counterpart Sergei Lavrov in Moscow on Friday.

The EU is due to hold an international donor conference for Syria next week. Most of its governments agree Assad cannot continue as president for peace talks to succeed.

“There will be a solution involving everyone who has influence on the region,” German Foreign Minister Heiko Maas said in Luxembourg.

“Nobody can imagine someone who uses chemical weapons against his own people to be part of this solution.”