The British man who was killed in the Sweden lorry attack has been named as 41-year-old Chris Bevington.
Two Swedes and a Belgian national were also killed when a hijacked lorry ploughed into pedestrians in Stockholm on Friday.
Rakhmat Akilov, a 39-year-old man from Uzbekistan, has been arrested on suspicion of "terrorist crimes through murder".
A second man has been arrested in relation to the deadly lorry attack on a Swedish department store, Sweden's national public broadcaster SVT has reported.
Police are said to believe he is connected to the other man who was arrested earlier.
SVT, citing police sources, said the man was arrested in the northern suburb Hjulsta.
The lorry crashed into shopping centre in Stockholm, killing at least four people, in what the Swedish prime minister has called a terror attack.
The main suspect in the Stockholm lorry attack has admitted to carrying out a terror crime, his defence lawyer said.
The Ahlens department store in Stockholm apologised "for a bad decision" in promoting the offer.
The British man who was killed in the Stockholm lorry attack has been named as Chris Bevington.