Donald Trump has been accused of confusing different US mass killings, after he sent condolences to the victims of a massacre in Texas in the wake of a shooting in California.
Four people were killed and ten injured on Tuesday morning after a gunman opened fire in several locations including an elementary school around 120 miles from Sacramento.
"May God be with the people of Sutherland Springs, Texas. The FBI and Law Enforcement has arrived," Mr Trump tweeted shortly after 8.30pm on Tuesday evening.
The US President's tweet appears to reference a shooting at a Texas church on 6 November, in which 26 people were killed.
"Even for Trump, this is astounding: he’s confused last week’s mass shooting with yesterday’s. Terrible insult to the victims of both," the European media director of Human Rights Watch said.
Piers Morgan, a supporter of Mr Trump, said: “At least get your mass shootings right, Mr President. This was last week. The new one is in California.”
The wording of the latest tweet closely resembles that of Mr Trump's post after the Texas shooting. Some Twitter users said it appeared as though the President had forgotten to change the location of the incident while copying an earlier tweet.
Others speculated he had accidentally posted a draft version of a tweet sent in the wake of the Texas atrocity.
Officials believe the shooting in California began as a "domestic violence incident", although the exact motivation for the killings is unknown.
Tehama Country Assistant Sheriff Phil Johnston said the gunman, who has not yet been named, tried to enter the Rancho Tehama Elementary school with the intention of shooting more children.
He was stopped after staff at the school heard shots and started their lockdown procedure, a measure which saved lives, Mr Johnston added.
"The shooter literally took his vehicle and rammed their fence and gate, entered the grounds on foot with a semiautomatic rifle," he told US media.
