Tyga has cancelled a gig in Sweden in a show of support for A$AP Rocky.

The 'F**kin' Problems' hitmaker has been locked up in a cell in Stockholm since July 3 when he was arrested on suspicion of assault following a street fight between him, his entourage and another man, and now his 29-year-old friend has pulled out of a show in the country in solidarity.

He tweeted: ''I have decided to cancel my show in Sweden this Sunday July 14. I will not be performing. #FREEASAPROCKY (sic)''

Rocky's manager, John Ehman, set up a Change.org petition to free the rapper earlier this week, branding the prison he's contained in as ''inhumane'' and claimed the 30-year-old star is being restricted of ''basic amenities'' and is facing ''horrific unsanitary conditions''.

On the page, he explained: ''The conditions of the facility are horrific. Some of the inhumane conditions Rocky and his colleagues are facing at the Stockholm Detention Center include 24/7 solitary confinement, restriction of amenities for the most basic of human functions, access to palatable and life sustaining food as well as unsanitary conditions.''

According to Ehman, the prosecutor told them they are looking into an ''additional two-week extension'' with a trail start date of around the middle to end of August, which would mean A$AP and his team would have a longer stay in the unfit cells.

He wrote: ''The prosecutor on the case has further communicated that he is working to receive an additional two-week extension for a trial to begin in mid - to end of August.

''To keep Rocky and his colleagues in jail pending the lengthy trial proceedings is a punishment before the fact, with no due process.''

He pleaded: ''Join us in the #JusticeForRocky movement and demand that Rocky be released from Swedish officials immediately.''

A source said the facility is dirty and smelly, and the hip-hop star is sleeping on a yoga mat with no blankets.

He was also reportedly only given an apple to eat once a day for the first five days and has had faeces hurled at him from the prisoner next door to him, who reportedly suffers from a mental health condition, and slams his head against the concrete wall.