Europe should boost its efforts to integrate newcomers from places like Syria, Iraq and Afghanistan, the U.N. refugee chief said Tuesday, calling it "one of the great challenges" of the future.

After more than 1 million people poured into the continent in 2015, High Commissioner for Refugees Filippo Grandi said in an interview that it is time for the European Union to engage in a reasoned debate on the issues of refugees that tore at its core.

"There's a time now to have this rational discussion - beyond the politicization of some of these issues, beyond the manipulation that some irresponsible politicians are carrying out, using this pretext to just get votes," Grandi said Tuesday.

"More thinking and more resources" should go into the integration of refugees, he said, because if done properly, it could "counter xenophobic tendencies, violent rejection and propaganda against foreigners."

Grandi spoke to The Associated Press at UNHCR's Geneva headquarters ahead of two summits in New York on refugees and migrants on Sept. 19-20 - including one convened by U.S. President Barack Obama - near the start of the U.N. General Assembly ministerial session.

One of the important "deliverables" in New York will be to promote "the notion of acceptance and inclusion," he said.

"We believe the time has come to look at integration programs more systematically, and this is, I think, one of the great challenges of the future," said Grandi, an Italian who previously headed the U.N. agency for Palestinian refugees and took over at UNHCR in January.

The influx to Europe has slowed, all but drying up through the favored route of last year - via Turkey across the Aegean to Greece - though hundreds of migrants still risk the far deadlier trek between Libya and Italy.

The massive inflows last year prompted a red-hot debate that ripped at the EU's fabric because countries like Germany and Austria were more welcoming, Greece and Italy more burdened, and a number of mostly eastern European countries resistant to take in refugees.

Work remains. Fewer than 4,000 people have been relocated from Greece and Italy out of the 160,000 that their EU partners had agreed to take in at the height of the crisis last year, Grandi said, but the relocation program was "picking up a bit."

Grandi says Europe also needs to handle possible rejections of asylum requests "with efficiency, so that people don't end up in limbo and disappear."

In the first quarter of 2016, the bloc granted asylum to nearly 90 percent of Syrian applicants, to about three-fourths of Eritrean applicants, and 62 percent of Iraqi applicants, according to the EU's statistics agency.