Istanbul - German Chancellor Angela Merkel offered Turkey visa concessions and financial aid in return for more support in dealing with Europe's refugee crisis in a meeting with Prime Minister Ahmet Davutoglu on Sunday.Merkel offered "to support a faster visa process" and to speed up negotiations on Turkey's bid to join the European Union, but expects Ankara to act more quickly in readmitting migrants deported from Germany in return, she said after the meeting in Istanbul."Turkey would like additional money, and I understand that," Merkel said, promising further financial aid for Turkey, which is a key transit country for migrants heading towards Europe.She cited the economy and Turkey's judiciary as new channels to be explored in talks on EU membership for Turkey.Davutoglu said he hopes that both sides of the deal will come into place in July 2016. He added that the measures offered by Germany should give new momentum to the "frozen" negotiations on EU membership.Turkey has demanded €3bn for the care of migrants within its borders - three times more than the EU's original offer.The majority of refugees travel via Turkey, which so far has taken in more than 2 million people from Syria alone, while Germany is expecting to take in as many as 1 million refugees this year. Whether the flow can be stemmed depends especially on the will of the political leadership in Ankara.Turkish citizens require a visa in order to enter the EU's borderless Schengen zone. The EU and Turkey initiated a "dialogue for visa liberalisation" in 2013 on the condition that Turkey takes in migrants who entered the EU illegally.The German chancellor is also scheduled to meet with President Recep Tayyip Erdogan during her visit, who has come up against fresh criticism from the international community in recent months for alleged human rights violations.European leaders have rarely visited Turkey since the 2013 crackdown on Gezi park protesters, pointing to the European Union's long-simmering frustrations with Erdogan.Some observers regard the visit to be a boost for Erdogan as it comes ahead of Turkey's general election on November 1, when voters will decide his own political fate.Many in the Turkish opposition have criticized the Merkel visit, with the largest party, the Republican People's Party (CHP), unhappy that no meeting with the opposition was planned."That she did not request a meeting with the CHP or with the opposition at all" gives the impression that she is participating in the election campaign, said Erdal Aksunger, chief advisor to CHP leader Kemal Kilicdaroglu.The pro-Kurdish Peoples' Democratic Party (HDP) further accused Merkel of engaging in a "dirty deal" with Erdogan. "It goes like this: 'Don't send us any more refugees, bring it to an end and get 3 billion euros,'" said HDP deputy leader Nazmi Gur.Merkel has to address Erdogan's Syria policies, Gur stated, saying the failure of these has led to the current migration "drama."Before the trip, Merkel however said that "on Sunday all the issues will be on the table."Those issues will include in addition to migration the conflict in Syria, visa restrictions, safe country of origin status, third-country status, the joint struggle against terrorism, and human rights in Turkey, she said.