"You are the thin blue line between civilisation and chaos", he told law enforcement officers gathered outside the US Capitol for the memorial service.
Vermont leaders recognize National Peace Officers Memorial Day by honoring the state's fallen officers.
The first National Police Memorial Day was proclaimed by President John F. Kennedy in 1962, and the week in which it falls would then be designated National Police Week.
Each year the nation loses an average of 140-160 law enforcement officers in the line of duty.
Trump said, "The attacks on our police must end, and they must end right now".
Trump revealed classified information to Russian Federation during recent meeting — WaPost
But he noted that he had a problem with Trump's tweet Friday, threatening to release possible tapes of conversations with Comey. Tillerson said nature of specific threats was discussed, but sources, methods or military operations were not talked about.
Gov. Greg Abbott was the keynote speaker for the event honoring the Texas troopers, special agents and Texas Rangers who have lost their lives in the line of duty.
The president signed a proclamation Monday declaring the day "Peace Officer Memorial Day" and the upcoming week "Police Week".
"We as a family, we as a brotherhood band together, we support these families year in and year out we're there for them", Cabell County Sheriff Chuck Zerkle said.
Pastor Joel Cauley from Relevant Church was the guest speaker at this year's service. "We thank them tremendously".
WASHINGTON (AP) - Decrying violence against police, President Donald Trump honored the "brave souls" of law enforcement on Monday and vowed his administration would look for ways to reduce violence against police.
An estimated 30,000 people attended the ceremony, including surviving family members, friends, law enforcement colleagues, and others, according to the Memorial Fund's press release.