BRUSSELS - Straining to cope with the influx, European countries are sharpening measures to stop the flow of refugees and migrants amid heightened security concerns following the Paris attacks last month.

Greek leaders last week finally agreed to hand over partial control of their borders to an EU border agency, after coming under heavy criticism for months that they were not doing enough to screen the more than 700,000 asylum seekers who have arrived on Greek shores this year.

The debate over stricter controls on refugees and migrants has exposed deep divisions in Europe over balancing humanitarian and security concerns. Those frictions have increased in the wake of revelations that two of the assailants in last month's Paris attacks arrived via the migrant trail.

European governments have been trying to pressure Greece to do more to secure its borders, as thousands more asylum seekers wash up every day. Greek authorities have struggled to perform cursory security screenings on those arriving. Many do not have passports or other identification.

"There are a certain number of improvements that need to be done," European Commission spokesman Margaritis Schinas said last week ahead of meetings focused on border security.

New steps agreed upon Friday will strengthen screenings, but the process will remain much weaker than in the United States and Britain, which investigate individual asylum seekers for months.

European interior ministers also gave preliminary approval to a new database to track the movements of airline passengers, a step that had been under discussion since 2007.

EU leaders pledged earlier this year to build special hotspot reception centers on Greece's islands to improve screening. But the new centers have not yet been completed, and they were designed to organize the distribution of the asylum seekers across Europe, not to perform rigorous security screenings.

In Belgium, refugees go through four screenings after lodging their claims, but asylum systems are so overwhelmed that it can take weeks to do so.

In an interview with a German newspaper last week, French Prime Minister Manuel Valls said that it was "not possible" for Europe to accommodate any more refugees, adding that it is threatening the union. In Germany, Angela Merkel is under pressure for her open-door policy, her ratings dipping. "Paris changes everything," Markus Soder, the Bavarian finance minister said. Meanwhile, in Eastern Europe, where nations have been particularly opposed to taking in migrants, fences have been erected.

"It's unfair to make the refugees a scapegoat because of what's happened in Paris," said Vanessa Saenen, a spokeswoman for the U.N. refugee agency in Brussels. "The end result is human misery."