UK Foreign Secretary William Hague described Monday as "a very important step forward" the interim agreement with Iran in recent weeks. "Now the implementation and coming into force of that deal is very important. There will be difficult negotiations in the coming months," he told reporters as he arrived for a meeting of EU foreign ministers in Brussels. "In the meantime we have to maintain our vigilance on sanctions and maintain the sanctions. We are not suspending the sanctions so Iran has a clear incentive to make a comprehensive deal on the nuclear issue," he noted. Hague said the situation on Ukraine will be "on all our minds today and we will be discussing this with the Russian foreign minister Sergey Lavrov". "The UK is very much in favour of closer relations between Europe and Ukraine and in favour of EU-Ukraine association agreement. Ukraine should be able to decide on this without external pressure," he said. Also important today is the situation in Syria , he said and added that they will discuss Syria with Lavrov in order to bring the regime and the opposition to the Geneva 2 meeting.