Mass shootings in Philadelphia, Baltimore and Fort Worth, Texas, have killed 10 people and wounded almost 40 others ahead of the Fourth of July holiday - a grim reminder of the decades-long failure to curb gun violence in the United States.
In Fort Worth, three people were killed and eight wounded in a mass shooting following a local festival to mark the US Independence Day holiday, police said on Tuesday.
In a separate mass shooting incident in Philadelphia on Monday evening, five people were killed and two were wounded, including a two-year-old boy and 13-year-old boy both shot in the legs, when a suspect in body armour and armed with an AR-15 opened fire on apparent strangers, according to local police.
The Monday night shootings came a day after two people were shot dead and 28 others injured, about half of them children, in a hail of gunfire at an outdoor neighbourhood block party in Baltimore.
The motives in all three recent shootings remained unclear.
US President Joe Biden condemned the violence and renewed his calls to tighten America's lax gun laws.
"Our nation has once again endured a wave of tragic and senseless shootings," the president said in a statement released on Tuesday.
Biden called on Republican representatives "to come to the table on meaningful, commonsense reforms".
Citing constitutional protections for gun ownership, Republicans in Congress have generally blocked attempts to significantly reform gun safety laws and oppose Biden's push to reinstate a ban on assault weapons.
Philadelphia officials pleaded with state and federal representatives to act.
"We are begging Congress to protect lives and do something about America's gun problem," Philadelphia Mayor Jim Kenney told a news conference.
The city's district attorney, Larry Krasner, asked Philadelphia state representatives for "reasonable legislation" of the type found in neighbouring New Jersey and Delaware.
"Some of that legislation might have made a difference here," Krasner told the same briefing.
Philadelphia police said the suspect was a 40-year-old man who had an AR-15 semiautomatic rifle and a 9mm pistol and who wore body armour and a ski mask.
The dead ranged in age from 15 to 59.
Philadelphia Police Commissioner Danielle Outlaw told reporters the shooter acted "knowingly and intentionally".
Krasner vowed to present multiple charges of murder and other offences at the shooter's first court hearing on Wednesday.
Police in Fort Worth said no arrests have been made in that shooting.
"We don't know if this is domestic-related, if it is gang-related," said Shawn Murray, a senior police official.
"It is too early to tell at this point."
In Baltimore, police have said they are seeking multiple suspects.
The latest shootings took place around the anniversary of last year's Highland Park mass shooting near Chicago, where seven people were killed and 48 others wounded at an Independence Day parade.
A 22-year-old man remains in custody after being indicted on 117 felony charges for the carnage.
There have been more than 340 mass shootings in the US so far this year, according to data collected by the Gun Violence Archive, which defines a mass shooting as an incident in which at least four people are shot, excluding the shooter.
