Hillary Clinton and Donald Trump campaign representatives confirmed they halted television ads for the anniversary tribute of the Sept. 11, 2001, terrorist attacks, keeping with a tradition of avoiding partisan presidential politics on 9/11. The New York-based nonprofit, 9/11 Day, sent letters to presidential candidates, asking them to stop their public political activities for Sunday's observance; the group instead encourages a national focus on service and remembrance.

9/11 Day representatives also asked Libertarian candidate Gary Johnson and Green Party nominee Jill Stein to "suspend all campaign activity" to honor the day.

9/11 Day president and co-founder, David Paine, said a one-day campaign moratorium would help rekindle the spirit of national unity and empathy that followed the attacks and marked Americans' moods of togetherness. Paine, along with his friend Jay Winuk, who lost his brother Glenn Winuk in the 9/11 attacks, have dedicated the better part of their lives over the past 14 years working to transform 9/11 from a day of evil into a day of good.

Trump and Clinton are the first New Yorkers to become their parties' nominees for president since nearly 3,000 people died in the Sept. 11 attacks. Both candidates incorporated their experiences from that tragic day into their campaign narratives, reports Yahoo News.

Clinton was senator from New York at the time of the attacks, and highlights her efforts to aid those affected by the World Trade Center collapse. She made frequent trips to the attack site and her staff has accentuated her efforts to help secure medical benefits for first responders sickened at ground zero.

Trump, meanwhile, said he donated construction equipment to the recovery effort and gave $100,000 to the memorial after touring it for the first time earlier this year. But he also received widespread criticism for claiming that "thousands and thousands" of Muslims in New Jersey celebrated when the towers toppled, a claim for which there is no proof, cites Yahoo.

Clinton attended the ground zero commemoration on the tenth anniversary of the attacks in 2011, when she was secretary of state. On Friday, Clinton staffers announced she will arrive at the memorial on Sunday morning before the annual moment of silence at 8:46 a.m., marking the minute the first plane struck the skyscraper's north tower, reports The Associated Press.

In 2009, the U.S. Congress and President Barack Obama passed bi-partisan national service legislation that formally designated Sept. 11 as a National Day of Service and Remembrance. Martin Luther King, Jr.'s birthday is the only other day of service officially established under federal law.

In 2008, 4 million people participated in the day of service, the year before Congress passed the legislation. Today, nearly 30 million Americans of all ages participate throughout the nation, by volunteering, supporting charities, and doing good deeds, according to independent research studies. That makes 9/11 Day the nation's largest annual day of charitable engagement, according to 9/11 Day.