Democratic U.S. presidential candidate Joe Biden on Monday called for rioters and looters to be prosecuted and slammed President Donald Trump for stoking violence in American cities gripped by protests over police brutality and racial inequality. 

Biden's speech in battleground state Pennsylvania was his most forceful counter yet to accusations by Trump that he is weak on crime and that leaders in his Democratic Party have lost control over the mass demonstrations that in some instances have turned violent. 

"Rioting is not protesting. Looting is not protesting. Setting fires is not protesting," Biden said from a converted steel mill in Pittsburgh. "It's lawlessness, plain and simple, and those who do it should be prosecuted." 

Trump, who trails his rival in opinion polls ahead of the November 3 election, has argued he stands for "law and order." The theme featured prominently at his nominating convention last week as he sought to motivate his political base and broaden his support.

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Republicans deny Trump is seeking to exacerbate violence with incendiary rhetoric. But Biden on Monday said Trump was sowing chaos. 

"This president long ago forfeited any moral leadership in this country," Biden said. "He can't stop the violence because for years he has fomented it." 

Trump, noting he had watched Biden's remarks, said in a tweet afterward that the former vice president seemed to blame police more than the "Rioters, Anarchists, Agitators, and Looters." 

Biden has repeatedly condemned disorder at demonstrations but has defended peaceful protesters, arguing justice must be served in cases of "unwarranted police violence."

Biden's visit to Pennsylvania, an important swing state that helped propel Trump to victory in 2016, marked an unusual trip afield for the former vice president, who has worked mostly from his Delaware home since March, when the coronavirus began spreading widely in the country. 

Trump and Vice President Mike Pence are both due to campaign in Pennsylvania this week.

In Pittsburgh, Biden depicted an America that was unsafe under Trump, with COVID-19 killing thousands of people a week and an economy in tatters. 

He said he wanted a country safe from the coronavirus, crime, racially motivated violence and "bad cops." 

"And let's be crystal clear: Safe from four more years of Donald Trump," he said, calling Trump's presidency "a toxic presence in our nation." 

"The incumbent president is incapable of telling us the truth, incapable of facing the facts and incapable of healing," Biden said. 

Samuel DeMarco, the Republican chairman in Allegheny County, where Biden was speaking, said his speech showed "desperation." 

"We have violent protests for 90 some days and now he's going to address it and try to blame Trump. Good luck with that," he said. 

Demonstrations have swept the United States since the killing in May of George Floyd, a Black man who died after a Minneapolis police officer knelt on his neck for nearly nine minutes. 

New protests erupted in Kenosha, Wisconsin, last week following the police shooting of Jacob Blake, another African American man, multiple times in front of his children, paralyzing him. 

Trump is set to visit Kenosha on Tuesday, but Democrats including the state's governor have urged him to stay away. The White House said it is making efforts to reach Blake's family but has been unable to connect.

Just 37.4 percent of active personnel in the U.S. military support Trump's re-election, while 43.1 percent back Biden, according to a new poll Monday.  

The poll by the Military Times and the Syracuse University Institute for Veterans and Military Families found that half of servicemen and women have an unfavorable view of Trump, and 42 percent strongly disapprove of him, compared to 38 percent with a favorable view of the Republican leader.  

Support for Trump fell from the previous poll in December 2019, when he had a 42 percent favorable rating.  

The poll of 1,018 people was taken before the recent Democratic and Republican party national conventions.  

Trump has boasted of strong support among the military and has touted his increase in funding for the Pentagon's budget. But that record is clouded by frequent disputes with the Pentagon's leadership, including popular Defense Secretary Jim Mattis who resigned in December 2018, and policy conflicts with the current secretary, Mark Esper, and Joint Chiefs Chair General Mark Milley. 

(With input from Reuters, AFP)