* Refugee crisis outstrips previous conflicts -aid chief
* Aid needed to help refugees, states hosting them
By Adrian Croft
LUXEMBOURG, April 22 (Reuters) - The Syrian crisis risks unsettling Lebanon and causing a humanitarian catastrophe in Europe's backyard, the European Union's humanitarian chief said on Monday, calling for a new drive to help refugees and strained neighbouring states.
Kristalina Georgieva said the two-year-old crisis in Syria was the most dramatic of recent years with 4.3 million people internally displaced and nearly 1.4 million refugees in neighbouring countries.
"Once we have the virus of inter-community violence spreading, what could the consequences be? Lebanon in flames, a humanitarian catastrophe of unimaginable proportions in a region that is close to our backyard," Georgieva said.
"So it is a tremendously important moral issue to help inside Syria and support the neighbourhood, but it is also in European self-interest to do so," she said.
The flow of refugees outside Syria was exceeding capacity to cope and placing great strain on neighbouring countries that are giving them shelter, she told Reuters in an interview on the sidelines of an EU foreign ministers' meeting that discussed the crisis.
Many communities sheltering refugees had turned hostile towards them and attitudes would turn even more negative if more skirmishes took place on Lebanese territory, Georgieva, who is from Bulgaria, said.
At least 70,000 people have been killed in Syria's civil war, which began as an uprising against President Bashar al-Assad but increasingly pits majority Sunnis against minority Alawites.
Syrian troops and Lebanese Shi'ite militias attacked rebel-held areas on the two countries' border on Sunday, in the heaviest clashes of the civil war in the strategic region, Lebanese and Syrian sources said.
Georgieva said Europe had provided some 600 million euros ($782 million) in humanitarian aid to Syria, of which 200 million had come from the EU's executive Commission.
The Commission had asked the European Parliament for permission to tap a 250-million-euro emergency reserve to increase aid. "Once this authorisation comes ... we will be announcing significant additional resources to Syria," she said.
She said the European Commission was looking at ways to mobilise more coordinated economic support for the refugees and host communities.
She also said she believed war crimes had been committed in Syria by both Assad's forces and the rebels.
"We have lost more than 30 humanitarian workers in Syria, primarily Syrians who work in our organisations, we have had kidnappings on a regular basis of humanitarian workers," she said.
"The main offender is the Assad regime, because Assad was the one who chose in July last year to use artillery and aircraft to bomb civilians and there is plenty of evidence to indicate that hospitals and bakeries have been targeted," she said.
Rebels had also shot at humanitarian convoys, she said.
"There is also some indication that use of sharia law is adding to the trauma of the Syrian people," she said.
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