European Union officials confirmed plans to stay away from a US-organised regional summit on Iran next month as foreign ministers sought agreement on Monday for a new body to overcome US President Donald Trump’s sanctions on Iran.

A meeting of foreign ministers in Brussels on Monday discussed the bloc’s plans to help European businesses trade with Iran despite American sanctions on trade and investment but officials said afterwards the talks did not reach a conclusion.

However Monday's meeting came as European countries were preparing to impose their own punishments on Tehran for its foreign and security policies.

Germany banned an Iranian airline from its airspace over accusations it took weapons and advisers to help support President Bashar Al Assad's forces in Syria's civil war.

A senior German government source said Berlin revoked the landing rights of Mahan Air because of suspicions it was being used for military purposes by Iran's Revolutionary Guards, and also on safety grounds.

Meanwhile asset freezes and travel bans were confirmed for five Syrians linked to strongman Bashar al-Assad's chemical weapons programme. The EU also sanctioned the Scientific Studies and Research Centre, an organisation accused of playing a role in the use of chemical weapons by the Syrian government.

The discussions also touched on EU representation to the coming Middle East summit in Poland, led by the US, on February 13-14. Ministers from several EU states have already said they would not attend.

Ms Mogherini said she will not take part as her officials privately described the event as an anti-Iran conference. Speaking on her way into the meeting, Ms Mogherini said she would be attending an African Union gathering in Ethiopia during the Warsaw meeting. She also revealed that there would be a joint meeting with the Arab League at its February summit.

Now we know why @FedericaMog is skipping #US-#Poland 'Middle East' summit in Warsaw on Feb 13-14. She'll be at an African Union summit, she says, in Addis. #Iran @SecPompeo — laurence Norman (@laurnorman) January 21, 2019

France is also unlikely to send its foreign minister, according to European diplomats. Luxembourg’s foreign minister said he would miss the event because of a prior arrangement. The UK and Germany have not yet taken any official position but are unlikely to show up.

The big decision facing the EU remains over the 2015 Iran nuclear deal as it seeks to create a so-called Special Purpose Vehicle to handle economic ties with Tehran despite the renewed American sanctions.

The SPV is expected to launch later this month but officials warn it will not be operational until later in the year. It will be registered in France, run by Germany and is likely to include Britain as a shareholder.

"There's a feeling of frustration among Britain, France and Germany, and others, after the first phase of diplomacy with Iran," a senior EU diplomat said. "We thought we could get some effort from the Iranians in several areas."

Iran has warned Europe may not be able to safeguard the nuclear deal and accused EU officials of dragging their feet.

Sanctions adopted earlier this month marked an unexpected shift in European diplomacy since the end of last year. Smaller, more dovish EU countries have joined France and Britain in a harder stance on Tehran, including considering new sanctions.

Those could include asset freezes and travel bans on Iran’s Revolutionary Guards and Iranians developing the country's ballistic missile programme.

The Brussels meeting also confirmed the two most senior officers in Russian military intelligence would face sanctions and formally identified the two agents accused by Britain of carrying out a chemical attack.

The EU accused the Russians -- two agents and the head and the deputy head of the GRU -- of orchestrating the "possession, transport and use" of the nerve agent used in Salisbury, England last March, in a failed attempt to assassinate a defector.

The agents are accused of travelling under the pseudonyms Alexander Petrov and Ruslan Boshirov, but the sanctions order confirms reports that identify them as Anatoly Chepiga and Alexander Mishkin, both 39 years old.