As you know we had a long agenda tonight. Let me start with migration.
Irregular flows on the Central Mediterranean route, that is from Africa to Italy, remain far too high and actually haven't changed for the last two years. That is why we discussed how to enhance our cooperation with Africa. The High Representative presented her diplomatic efforts with five priority countries, namely Senegal, Mali, Niger, Nigeria and Ethiopia. The goal is to prevent illegal migration to Italy and to the rest of Europe, and to ensure effective returns of irregular migrants. The High Representative was given our support and will assess progress in December.
When it comes to the Eastern Mediterranean route, the situation has improved, with a 98% drop in arrivals since last year. That is why leaders could discuss getting back to Schengen. We all agreed that the goal is to lift temporary border controls over time, which will be accompanied by the reinforcement of the external borders. Leaders also discussed the question of solidarity among Member States during this crisis. We will consider concrete proposals in December, but the important thing today was to agree that there would be no solidarity "à la carte". We will be working on effective solidarity instead.
This evening we had a broad discussion about Russia. Leaders emphasised all sorts of Russian activities, from airspace violations, disinformation campaigns, cyber attacks, interference into the political processes in the EU and beyond, hybrid tools in the Balkans, to developments in the MH17 investigation. Given these examples, it is clear that Russia's strategy is to weaken the EU. We have a sober assessment of this reality, and no illusions. Increasing tensions with Russia is not our aim. We are simply reacting to steps taken by Russia. Of course the EU is always ready to engage in dialogue. But we will never compromise our values or principles. That is why leaders agreed to stay the course. And above all to keep the unity of the EU.
I want to make one specific point on the MH17 investigation. Leaders expressed their full support for the Dutch government in the ongoing investigation. All States that are in a position to assist the investigation and prosecution of those responsible, must do so.
Leaders also discussed Syria. They strongly condemned the attacks by the Syrian regime and its allies, notably Russia, on civilians in Aleppo. The EU is calling for an end to the atrocities and an immediate cessation of hostilities. It will consider all available options, if these atrocities continue. We have asked the High Representative to pursue further diplomatic and humanitarian efforts.
Finally, let me say that we were glad to welcome Prime Minister May to her first European Council. Prime Minister May confirmed that the UK will invoke Article 50 before the end of March next year. There will be no negotiations until Article 50 is triggered by the UK so we didn't discuss Brexit tonight. However, the basic principles and rules, namely the Single Market and indivisibility of the four freedoms, will remain our firm stance. Thank you.