The German and Italian leaders Friday pledged to tackle Europe's migrant influx but failed to resolve discord on an EU deal with Turkey to limit arrivals, a day after Berlin moved to tighten asylum rules.

Chancellor Angela Merkel said that, with 2,000 new asylum seekers entering the Balkans every day, the European Union "urgently" needs to implement a deal that asks Turkey to better protect its borders in return for financial support.

"We must fight illegality," combat human traffickers and avoid migrant deaths at sea, Merkel said at a Berlin press conference with Italian Prime Minister Matteo Renzi.

Renzi, who has stalled on signing off on the three-billion-euro ($3.3 billion) EU payment to Ankara and traded barbs with Brussels, said he was still seeking clarification about the details from the EU executive.

"We are still waiting for the answers to specific questions we sent to the (European) Commission," he said, adding that once there is clarity, "there can be no doubt that we will make our contribution".

Italy has questioned how much of the money should come from the EU budget, and how much control the bloc will have over how Ankara spends the funds.

Responding to recent German criticism that Italy has been slow to set up "hotspot" migrant registration centres, he said that Italian police were now "registering 100 percent of refugees" and taking their photos and fingerprints.

In a diplomatic show of unity after Renzi has repeatedly criticised "German dominance" in EU affairs, both leaders said that the migrant crisis can only be solved if the 28 members of the bloc work together.

Renzi added that "for many years it seemed that the problem of migration was a purely Italian problem. Today we know that it is a European problem. And I believe it will last for months, maybe years."

Merkel, after a decade in power, has come under fierce pressure to reverse her open-arms migrant policy, with emotions heightened after a rash of sexual assaults in Cologne on New Year's Eve police blamed mostly on North Africans and Arabs.

She has seen her long-stellar poll ratings slide ahead of three state elections in March. A poll published Friday by news weekly Focus found that 40 percent of respondents want Merkel to resign.

Late Thursday, Merkel's coalition government, after months of wrangling, hammered out a deal to limit numbers by blocking some family reunifications and declaring three North African nations "safe countries of origin."

The agreement means citizens of Algeria, Morocco and Tunisia will have little chance of gaining political asylum, mirroring steps Germany took for several Balkan countries last year.

Germany will also block family reunifications for two years for rejected asylum seekers who can't be deported because they face the threat of torture or the death penalty in their own country.

Across Europe, debate has raged on how to handle the biggest migrant wave since World War II, with Sweden and Finland announcing plans to deport tens of thousands of failed asylum seekers.

Several eastern European countries have sealed their borders, and Hungary's hardline Prime Minister Victor Orban reiterated Friday that "migration is a security issue", linking it to "the threat of terrorism and crime".

Bulgarian Prime Minister Bokyo Borisov demanded the closure of the external borders of the passport-free Schengen area, arguing that rather than spend money on migrants, Europe should stop them from coming.

With Greece under EU pressure to better control the bloc's outer borders, Human Rights Watch on Friday said that "turning the country into a warehouse (for migrants) is no solution to Europe's refugee crisis".

In Germany, the inflow has fallen from thousands to hundreds a day in recent weeks amid harsh winter weather, and the government is desperate to keep it that way.

"We must seize the window of opportunity that has opened," said Merkel's migrant policy coordinator Peter Altmaier.

"Our goal must be for refugee numbers not to rise again after the end of the winter storms but for them to keep going down."

So far this year, more than 55,500 people have reached Europe's shores, the International Organization of Migration said.

Of the total, 244 died on the way to Greece and Italy, a far higher toll than this time last year, the IOM's Joel Millman said, adding that perhaps traffickers were rushing as they feared more border clampdowns.

"Clearly something has changed, because these boats are less seaworthy, and they seem to be leaving packed in greater numbers," Millman said.

"So that speaks to perhaps a panic in the market that this is not going to last much longer."