WASHINGTON — The United States must ensure that immigrants are fully included in the fabric of American society to prevent violent ideologies from taking root at home, Vice President Joe Biden said Tuesday as he opened a White House summit on countering extremism and radicalization.

Joining local elected officials, community leaders and religious figures, Biden portrayed the U.S. as far better positioned than Europe, thanks to what he called America’s successful record at cultural integration. He said societies must offer immigrants an “affirmative alternative” to extremism, cautioning that military force alone could not address the threat.

Across the Atlantic, deadly terrorist attacks in France, Belgium and Denmark have left Europeans feeling vulnerable to the type of violent ideology promoted by the Islamic State group and once thought to be confined mostly to the Middle East and North Africa.

“National security flows from a sense of community,” Biden said, adding that the most important lesson the U.S. can learn is that “inclusion counts.”

The White House has sought to use the three-day conference in Washington to stir a sense of urgency about the challenge of preventing home-grown terrorism and the radicalization and recruitment of Americans, particularly disaffected young people. Yet it comes as the Obama administration has struggled to match its stated strategy for fighting IS and other Islamic extremist groups with the realities on the ground in Libya, Yemen and other Mideast hotspots.

Today, President Barack Obama was to address a gathering at the White House examining the response from U.S. cities, then speak at the State Department on Thursday at a gathering of representatives from roughly 60 countries. The United Kingdom, Jordan, Egypt, the United Arab Emirates, Kuwait and France are expected to attend.

Global concerns that the Islamic State is drawing interest and support from communities far away from Iraq and Syria have only grown in recent days. Egypt launched airstrikes against IS positions in Libya, where the group posted video of 21 Egyptian Coptic Christians being beheaded, and the U.N. Security Council is considering its own response. Denmark is reeling from a weekend shooting spree by a 22-year-old gunman that authorities believe may have been radicalized in prison.

Biden, in his remarks, held up Boston, Los Angeles and Minneapolis as examples of communities moving ahead with programs to counter extremism locally. He said the goal was to bring together broad coalitions of community leaders so that all Americans — and particularly Muslims — would feel like “we see them.”

“We haven’t always gotten it right,” Biden said. “But we have a lot of experience integrating communities into the American system, the American dream.”