BERLIN—The number of migrants entering Germany each day has declined by more than half in the past two weeks, the government’s top security official said on Monday, describing signs of a slowdown even as the total number of migrant arrivals this year approached one million.

About 965,000 asylum-seekers came to Germany this year through November, German Interior Minister Thomas de Maizière said, including a record-setting 206,000 people in November. He cautioned that it wasn’t clear how many of them had moved on to other European countries and were applying for asylum there.

The intensity of the migration flow into Germany has declined significantly, Mr. de Maizière added. In the past one to two weeks, German authorities have been registering about 2,000 to 3,000 daily arrivals, he said—down from 8,000 or more a day earlier this fall. He said the decline was a result of both worsening weather and greater efforts by Turkey to limit the numbers of people departing from its shores for Greece.

“This is very gratifying and good,” Mr. de Maizière said of the recent decline. “This is not yet a turning point, but it is a good development.”

The new numbers offered the latest indication of the scale of Europe’s migration crisis and of the pressure on German Chancellor Angela Merkel to further limit the number of people trying to enter the European Union.

Ms. Merkel has been trying to come up with a common EU strategy to deal with the influx of refugees and other migrants from the Middle East and elsewhere, resisting calls domestically that Germany start turning back migrants at its own borders.

Germany, with its welcoming message to refugees and generous asylum laws, has been the top EU destination for the millions of people fleeing war and poverty. Other EU countries have criticized Ms. Merkel’s open-door policy for worsening the crisis by encouraging more people to make the trek.

Mr. de Maizière indicated that one element of Ms. Merkel’s strategy—a recent EU agreement with Turkey in which the country pledged to step up prevention illegal migration to Europe in exchange for help managing the millions of refugees in Turkey—was showing early signs of bearing fruit. German federal police recorded 7,500 migrants in a day as recently as Nov. 25, but just 3,293 on Sunday, a spokesman said.

But another prong of Ms. Merkel’s effort—convincing other EU countries to volunteer to take in refugees directly from Turkey—still faces resistance across the bloc.

New data released by the government on Monday showed Syrians and Afghans still made up the greatest share of migrants, with 97,463 and 44,846 arrivals, respectively, registered in November. The more-than-200,000 new comers in November represented an increase of 25,000 over the prior month.

The wave of migration has created a huge backlog in Germany’s bureaucracy. Despite the much larger number of new arrivals, only 57,816 people were able to formally apply for asylum in November, the Interior Ministry said.