US President Barack Obama delivers remarks at the Islamic Society of Baltimore mosque in Catonsville, Maryland, Feb 3, 2016. [Photo/Agencies]

WASHINGTON - US President Barack Obama on Wednesday slammed anti-Muslim rhetoric and appealed for tolerance for millions of Muslims in the country during his first visit to a US mosque as president.

"We've heard inexcusable political rhetoric against Muslim-Americans that has no place anywhere in our country," said Obama in an address at the Islamic Society of Baltimore, Maryland.

"You have seen too often people conflating the horrific acts of terrorism with the beliefs of an entire faith," he said, adding that the anti-Muslim rhetoric started since 9/11 attacks but more recently since the attacks in Paris and San Bernardino, California.

"We've seen children bullied, we've seen mosques vandalized," said Obama. "That's not who we are."

Though Obama did not specifically name anyone who, in his words, resorted to "inexcusable" anti-Muslim rhetoric in the political sphere, White House spokesman Josh Earnest on Tuesday took a clear jab at some Republicans who he said with "an alarming willingness" tried to "marginalize law-abiding, patriotic Muslim Americans".

"It's just offensive to a lot of Americans who recognize that those kinds of cynical political tactics run directly contrary to the values ... in this country," said Earnest at Tuesday's briefing.

With the looming threat of the extremist group Islamic State to US homeland security, Republican presidential candidate Donald Trump had recently called for a ban on all Muslims entering the United States.

Obama's address also came at a time when almost half of Americans think at least some US Muslims have traces of animosity toward the United States.

According to a new Pew survey released on Wednesday, about 49 percent Americans think at least some US Muslims are anti-American.