Residents of a Maine town near the scene of one of the US’s worst mass shootings in history have been asked to “shelter in place” for a second day, as a police manhunt continues.

Maine police are searching for Robert Card, a US Army reservist wanted for murder after 18 people were killed and 13 were wounded in shooting attacks at a bowling alley and a bar in the city of Lewiston the previous night.

In an expanding manhunt, police fanned out across southern Maine with an arrest warrant for Card, a sergeant at a nearby US Army Reserve base who law enforcement officials said had been temporarily committed to a mental health facility over the northern summer.

Police circulated photographs of a bearded man in a brown hooded sweatshirt and jeans at one of the crime scenes armed with what appeared to be a semi-automatic rifle.

Public school districts in the area cancelled classes on Thursday and police urged residents to stay indoors.

In the town of Lisbon, about 13 kilometres south-east of Lewiston, residents were told to continue to shelter in place overnight as the search went on.

“Shelter-in-Place: We kindly request all Lisbon residents to continue sheltering in place throughout the overnight hours. Your safety is our top priority,” the town said in an update on Thursday night (local time).

All Lisbon schools and town-owned buildings were to be clsoed on Friday.

There was an eerie quiet in Lewiston and Lisbon on Thursday, with almost no cars on the roads and just a few people outside. Many downtown businesses appeared to be closed. There was an illuminated “shelter in place” sign on Lewiston’s Main Street.

Earlier, dozens of law enforcement officials returned to Card’s home in Bowdoin, 19 kilometres east of Lewiston, to search it. A spokesperson for Maine’s Department of Public Safety, Shannon Moss, said they were “not positive Robert Card is in this house”, adding officials were “simply doing our due diligence”.

Sources told CNN investigators were looking for items like computers, notes, weapons and any evidence that might indicate a plan to carry out the shootings.

The US ABC is reporting investigators found a note at the home addressed to Card’s son. It was described it as a suicide note that contained rantings, as well as basic personal information like bank account details.

CNN reported hearing heard loud bangs near the address on Thursday night, including someone shouting “FBI” through a bullhorn.

State and local investigators did a similar-style entry and search at another location, as well as a search of Card’s car on Thursday, CNN said.

Robert Card remains on the run, 24 hours after the attacks. Photo: Androscoggin County Sheriff’s Office

Card, 40, is a petroleum supply specialist at the US Army Reserve base in Saco, Maine. He who had never been deployed in combat since enlisting in 2002, the US Army said.

A Maine law enforcement bulletin described Card as a trained firearms instructor who recently said that he had been hearing voices and had other mental health issues.

He threatened to shoot up the National Guard base in Saco and was “reported to have been committed to mental health facility for two weeks during summer 2023 and subsequently released”, according to the bulletin from the Maine Information & Analysis Centre, a unit of the state police. Reuters could not confirm the details reported in the bulletin.

The attacks began shortly before 7pm (local time) at the Just-In-Time Recreation bowling alley, where one female patron and six males were shot dead, police said, without giving the victims’ ages.

Within about 10 minutes, they received reports of a shooting at Schemengees Bar & Grille Restaurant, about five kilometres away. Eight males were fatally shot dead there, police said.

Three victims who were taken to hospitals later died of their injuries. A further eight are in a critical condition.

Guns are lightly regulated in Maine, a largely rural state near the northeast border with Canada where about half of all adults live in a household with a gun, according to a 2020 study by RAND Corporation.

Maine does not require a permit to buy or carry a gun, and it does not have so-called “red flag” laws that some other US states have, which allow law enforcement to temporarily disarm people deemed to be dangerous.

“This is a dark day for Maine,” Governor Janet Mills, a Democrat, said at a press conference.

“Mr Card is considered armed and dangerous and police advise that Maine people should not approach him under any circumstances.”

US President Joe Biden, echoing other officials, said in a statement that he mourned “yet another senseless and tragic mass shooting” in a nation where deadly gun violence is commonplace.

He again urged Congress to pass a ban on high-capacity magazines and other gun regulations.

Biden had spoken to state officials to offer the federal government’s support and ordered flags to be flown at half-mast until Monday to honour the victims, his office said.

The 18 fatalities in the shootings on Wednesday is close to the annual number of homicides that normally occur in Maine, which has fluctuated between 16 and 29 since 2012, according to Maine State Police.

-with AAP