By Paul Carrel and Michael Nienaber
BERLIN (Reuters) - German Chancellor Angela Merkel stressed Turkey's "key role" in solving Europe's refugee crisis ahead of a weekend visit to Ankara, as her government tightened asylum rules on Thursday to stem an influx of new arrivals.
With a bitterly divided EU struggling to cope with hundreds of thousands of people fleeing war and poverty in the Middle East, Asia and Africa, securing cooperation of non-member Turkey is seen as increasingly central to managing the problem.
Merkel, facing pressure from her own conservatives to take a harder line on refugees, described the challenge of dealing with the migrant crisis as a "historic task" and said the European Union should do more to help Ankara deal with the influx.
"Without a doubt Turkey plays a key role in this situation," she told the Bundestag lower house of parliament before attending a European Union summit in Brussels later on Thursday.
"Most war refugees who come to Europe travel via Turkey. We won't be able to order and stem the refugee movement without working together with Turkey," she added.
This included giving Turkey more support in caring for the refugees and providing humanitarian aid, as well as helping to secure borders and combat criminal smuggling rings, she said.
A favored destination for migrants, Germany expects a record-breaking 800,000 to a million new arrivals this year.
In Berlin, lawmakers approved measures to tackle the crisis, including speeding up asylum and deportation procedures and reducing incentives for economic migrants to come to Germany.
"The number of those coming to us this year is simply too high," said Interior Minister Thomas de Maiziere, though he refused to commit to a cap and echoed Merkel in calling for an international solution to the crisis.
Merkel is under particular pressure from the Bavarian Christian Social Union (CSU), sister party of her Christian Democrats (CDU) - to take a harder line on refugees, though she has rejected calls to turn away asylum seekers.
In Munich, CSU leader Horst Seehofer said Germany and Europe would fail unless they limited immigration.
"If we don't set limits on the number of immigrants, the population will set them for us by withdrawing trust," he said.
European leaders meet in Brussels on Thursday to discuss strategies for dealing with tide of refugees trying to enter Europe. The agenda includes increasing cooperation with Turkey and other countries bordering Syria to try to keep millions of refugees in the region.
Merkel also plans to visit Turkey on Sunday for talks with President Tayyip Erdogan and Prime Minister Ahmet Davutoglu.
The chancellor said she was sensitive to concerns in Germany about the need to assert European values in talks with Turkey while also addressing the refugee crisis.
Turning to Turkey's longstanding application to join the EU, she added: "Treaties will be adhered to, and the EU's negotiations with Turkey conducted without pre-judging."
A senior official in Berlin told Reuters on Wednesday that the German government is willing to support an EU proposal to put Turkey on a list of "safe countries" whose citizens have little chance of being granted asylum in Europe.
Germany has previously been skeptical of the proposal, mainly because of Ankara's human rights record and its treatment of the Kurdish minority.
Merkel said the conflict in Syria, which borders Turkey, was the biggest cause of the migrant flows to Europe.
"To stabilize the situation in this country, so terribly afflicted by terror and violence, and to bring it peace in the long-term of course we need a process of political dialogue which includes Russia and other international actors, including regional actors," she said.
(Additional reporting by Caroline Copley; Editing by Tom Heneghan and Andrew Heavens)