Country endured 28 mass killings – a total of 140 victims – amid uptick in gun violence and calls by some for stricter laws.

The AP analysis, published on Friday, said 140 victims were killed during that period. All but one of the mass killings – incidents in which four or more people are slain not including the perpetrator – involved firearms.

“What a ghastly milestone,” Brent Leatherwood, whose three children were in class at a private Christian school in Nashville in March when a former student fatally shot six people, told the AP. “You never think your family would be a part of a statistic like that.”

A database maintained by The Associated Press and USA Today in partnership with Northeastern University has been tracking large-scale violence since 2006.

The 2023 milestone beat the previous record of 27 mass killings, which was only set in the second half of 2022. James Alan Fox, a criminology professor at Northeastern University, never imagined records like this when he began overseeing the database about five years ago.

“We used to say there were two to three dozen a year,” Fox told AP. “The fact that there’s 28 in half a year is a staggering statistic.”

Mass killings are rising with an overall uptick in gun violence. The country has endured 377 mass shootings since the start of the year, according to the Gun Violence Archives database.

Around the July 4 holiday, marking the US Independence Day, multiple mass shootings killed and injured dozens of people across the country, including in the capital, Washington, DC, prompting renewed calls for stricter gun laws.

Earlier this month, President Joe Biden decried the “wave of tragic and senseless” shootings and called on Republicans in Congress to join him in pursuing “meaningful, commonsense” gun reforms.

“It is within our power to once again ban assault weapons and high-capacity magazines, to require safe storage of guns, to end gun manufacturers’ immunity from liability, and to enact universal background checks,” Biden – a Democrat – said in a statement on July 4.

Gun laws have been a polarising political issue in the US. While Democrats call for tighter regulations, Republicans view gun ownership as an unquestionable right granted by the Second Amendment of the US Constitution.

Experts have attributed the rising bloodshed to a growing population with an increased number of guns in the US. Yet for all the headlines, mass killings are statistically rare and represent a fraction of the country’s overall gun violence.

“We need to keep it in perspective,” Fox said.

Despite the unprecedented carnage, the National Rifle Association (NRA), a pro-gun lobby group, maintains fierce opposition to regulating firearms, including AR-15-style rifles and similar weapons.

“Joe Biden and Kamala Harris’ constant efforts to gut the Second Amendment will not usher in safety for Americans; instead, it will only embolden criminals,” NRA spokesman Billy McLaughlin told the AP in a statement.

“That is why the NRA continues our fight for self-defense laws. Rest assured, we will never bow, we will never retreat, and we will never apologize for championing the self-defense rights of law-abiding Americans.”