Two families from Romania and India were found dead in the St Lawrence River by Canadian police near the US-Canada border on Thursday, with one infant still missing.

Six bodies were recovered by police, who said the families were likely trying to enter the US illegally.

They were found late Thursday afternoon in a marsh near an overturned boat, authorities said.

A search of the area is ongoing to find the missing infant.

Police said the first body was found around 17:00 local time (21:00 GMT) in a marsh in Tsi Snaihne in Akwesasne, a Mohawk territory located right between the US-Canada border.

The other bodies were then found nearby. Their identities have not yet been released by police.

"The six individuals are believed to be from two families, one of Romanian descent and the other believed to be citizens of India," Lee-Ann O'Brien, deputy chief of Akwesasne Mohawk Police Service, told reporters in a news conference on Friday.

"Police believe one infant from the Romanian family has not been located and we'll continue searching," she added.

"All are believed to have been attempting illegal entry into the US from Canada."

Police said one of the bodies found was that of a child under the age of three.

According to Canadian news outlets CBC and CTV, the child was found with a Canadian passport and was a member of the Romanian family.

Both outlets also reported that the bodies were found after members of the Canadian military spotted an overturned boat nearby.

Authorities at the time were conducting a search for a missing boater in the area, 30-year-old Casey Oakes. Police said it is unclear whether there was any connection between Mr Oakes and the families, and Mr Oakes remains missing.

The bodies were found in the Quebec area of Akwesasne, a Mohawk community whose territory includes parts of Ontario, Quebec and New York State. It is located about 120 km west of Montreal.

Bodies of people attempting to cross into the US from Canada have been found at other locations in recent months.

In January, police in Canada found the bodies of four people, including an infant, in a snow field near Emerson, Manitoba, by the US-Canada border. The dead are believed to be a family from India, US officials said.

A Montreal man was also found dead near the US-Canada border in December. Fritznel Richard, 44, was trying to cross into the US to reunite with his wife and child.

US border agents have noted an uptick of people crossing back from Canada.

In January, US Border Patrol apprehended 367 people attempting to cross north to south - more than the number of such crossings in the last 12 years combined. (BBC)

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