WASHINGTON, (Reuters) – Republican presidential candidate Donald Trump said he would implement a database to keep track of Muslims in the United States as part of his immigration policy.

Trump, interviewed by NBC News after a campaign appearance in Iowa on Thursday night, was asked how a database tracking Muslims differed from efforts last century to track Jews in Nazi Germany, and said: “You tell me.”

His comments come amid renewed security concerns following the Islamic State attacks in Paris last week that killed at least 129 people and U.S. plans to take in 10,000 refugees from Syria.

Trump, who has made immigration policy a key part of his campaign for the Republican nomination in the November 2016 presidential election, told NBC a database would be part of his plan.

“I would certainly implement that, absolutely,” he said, adding that the United States also should control its border with Mexico with a wall, something he has long touted.