Foreign Secretary William Hague has warned extremism in Syria could flourish if the European Union refuses to ease an arms embargo preventing the supply of weapons to rebels opposed to President Bashar al Assad.

Speaking in Brussels ahead of a meeting of EU foreign ministers, where he attempted to persuade his counterparts of the need to lift restrictions on the supply of weapons, Mr Hague said the current state of affairs could not be allowed to continue.

The EU embargo expires at the end of the month and Mr Hague indicated each country would be able to adopt its own approach if no common position could be established to replace the current sanctions regime.

The UK and France have led calls for the embargo to be relaxed but Mr Hague acknowledged their position did not have universal support within Europe.

He insisted amending the embargo would force the Assad regime to take peace talks seriously. He said: "There is a difference over what it's appropriate now for the EU to do. In our view it is important to show we are prepared to amend our arms embargo so the Assad regime gets a clear signal it has to negotiate seriously.

"Therefore, for us, amending the embargo is part of supporting the diplomatic work to bring about the political solution.

"We also have to think about what is happening to people in Syria. How long can we go on with people having every weapon that's ever been devised dropped on them while most of the world denies them the means to defend themselves? That is creating extremism, it is radicalising people.

"We are reaching the limit of how long we can go on with that situation."

Mr Hague added: "It is important we are doing the right thing for Syria – that is more important than whether the EU is able to stick together on every detail of this. I think we will have to see how the discussion goes, but we are prepared for every eventuality."

Anna Macdonald, head of arms control at Oxfam, warned supplying weapons would mean "adding fuel to the fire" in Syria.

She said: "We are concerned supplying arms to the opposition won't level the playing field, in fact it will fuel a deadly arms race that will have even worse consequences for civilians. The millions of people suffering in Syria right now don't need more arms, they need aid. Providing more arms in times of conflict is simply adding fuel to the fire."

The peace process must be exhausted before any other solutions are considered, she added.

Shadow Foreign Secretary Douglas Alexander said: "William Hague should be asking both is it legal, and is it advisable to send arms to Syria's rebels.

"How would the Government prevent British-supplied weapons falling into the wrong hands, and how does supplying weapons help to secure a lasting peace?

"Syria today is awash with arms and in the House of Commons last week MPs on all sides expressed real concern about the identity, intent and tactics of some of the rebel forces."