Image copyright Emma Kelty

Three people have been arrested following the death of a British woman who disappeared while kayaking up the Amazon, police in Brazil have said.

Emma Kelty, 43, of London, went missing last week. Her body has not been found.

While drug traffickers and pirates operate in the region, police say she had been robbed, with one of the suspects claiming she was shot twice.

Ms Kelty's family said they were extremely proud of her and "her strength would be sorely missed".

The Foreign Office said earlier it was "supporting the family of a British woman following her death in Brazil".

Ms Kelty disappeared in the upper stretches of the Amazon in northern Brazil, often referred to as the Solimoes River - an area known for pirate attacks and drug traffickers.

Some of her belongings, including her kayak, were found by the Brazilian navy on Friday, according to police chief Ivo Martins.

According to the chief of the Amazonas state police, the robbers had attempted to sell Ms Kelty's two mobile phones, GoPro camera and a tablet computer.

'Active and determined'

Frederico Mendes told BBC Brasil he suspected the Briton had been killed because she had been seen by local people the day before.

Ms Kelty was 42 days into a 4,000-mile trip along the Amazon river from its source to the Atlantic Ocean and had been documenting her trip on Twitter.

Ms Kelty's brothers Piers and Giles and sister Natasha said in a statement: "Emma was an active and determined sister who challenged herself, latterly through her adventures on the Pacific Coast Trail, as well as in the South Pole and Amazon River.

"In a world that is today a much smaller place, the explorer in our sister found herself seeking ways to prove that challenges were achievable.

"We wish to give our immense thanks to the Brazilian navy, police and Foreign Office for their action and support."

Her last tweet was on 13 September. The day before she tweeted that she saw "30 to 50 men armed with rifles and arrows in boats".

Ms Kelty, in a Facebook post on 10 September, wrote about the dangers of the area she was entering: "So in or near Coari (100km away) I will have my boat stolen and I will be killed too. Nice."

After travelling past the town, she posted two days later: "Am in the clear. All OK".

Image copyright Emma Kelty Image caption Emma Kelty posted a picture of her tent on 10 September, a few days before she went missing

The former head teacher's previous expeditions included a solo ski trip to the South Pole in January.

Speaking to BBC Surrey in February, she talked about the risks she would face in the Amazon, including "people who organ-harvest and rob and fire guns".

Asked if she was risking her life on these adventures, she said: "Oh yes, I mean that's half the challenge.

"But it's about minimising the risk. I'm going to a self-defence course which is going to be tailored to de-arming people, so if I do come across that situation at least I'm prepared for it."

Olie Hunter Smart, an explorer who completed a similar route in 2015, said Coari was an area known for its danger.

He had met Ms Kelty before her trip to help her plan for the journey.

Mr Smart, who is currently walking the length of India, said: "The Emma that I met was an incredibly brave and courageous person who lived life to the full.

"My thoughts go out to her close friends and family at this very sad time."