DR Congo's justice minister was briefly arrested on Saturday, the latest twist in a crisis over proposed judicial reforms that have shaken the governing coalition and triggered violent street protests.

The action against Celestin Tunda Ya Kasende came a day after he clashed with President Felix Tshisekedi over the contested legal changes, according to a ministerial source.

The reforms, proposed by supporters of the still-influential former president Joseph Kabila, have caused a damaging rift in Tshisekedi's fragile coalition.

Tunda Ya Kasenda, a lawyer by profession who also holds the rank of deputy prime minister, had told AFP by phone shortly before his arrest that about a dozen officers were surrounding his Kinshasa home.

"I am serene. I'm a member of the government and I have immunity," said the minister, a Kabila ally.

He was taken to the prosecutor's office, according to lawmaker Felix Kabange Numbi, who said Tunda Ya Kasenda faced accusations of forgery but gave no other details.

The minister was later released after being questioned by a magistrate.

"No charge has been filed," one of the minister's supporters, Francois Nzekuye, told AFP. "The prosecutor himself noted that there was no case, it was a pointless hassle."

Legal sources confirmed that no charges had been filed.

- Kabila camp in the streets -
Kasende's arrest, albeit brief, brought other supporters of Kabila out on to the streets, a group of them gathering in front of the prosecutors' office in solidarity.

Among them were several senior members of the Common Front for Congo (FCC), a coalition close to Kabila, who remains a behind-the-scenes force in national politics. Kabila's own twin sister, Janet, was also present.

After Kasende was released, party members celebrated at the headquarters of the former president.

"What we have been through today is the birth of a dictatorship," said Emmanuel Ramazini Shadary, Kabila's protege and the defeated candidate in the 2018 presidential election.

"Tomorrow we are going to announce our action plan to put an end to this chaos, to this dictatorship."

Several sources reported that Prime Minister Sylvestre Ilunga, another Kabila supporter, had threatened to resign after Kasende was arrested, a move that would have put an end to the ruling coalition.

The controversial judicial reforms include proposals to define the powers of judges, which critics say is a ploy to muzzle the judiciary in a country known for its instability.

They were put forward by the FCC. 

The FCC sits in an uneasy coalition with Tshisekedi's Union for Democracy and Social Progress (UDPS) and it accounts for most of the 66 government ministers as well as the prime minister.

- Reprimanded by the president -
Over two days this week, angry demonstrators, mainly UDPS supporters and some armed with petrol bombs, blocked traffic outside parliament, erecting barriers and burning tyres in a protest over the legal changes.

Some demonstrators also attacked the homes of Kabila supporters. Police said 18 people were injured, including police officers, and 40 arrests made over the two days.

The justice minister's arrest came after he was reprimanded during a cabinet meeting by a furious Tshisekedi, according to ministerial sources.

He had apparently informed parliament about the government's views on sections of the reforms involving the status of magistrates -- without consulting the president who was said to have abruptly walked out of the meeting and slammed the door.

Tshisekedi's office denied this version of events, saying he had to leave the meeting for a video conference with other African leaders.  

Former parliament speaker Aubin Minaku, one of the people behind the proposed amendments, said this week that the aim of the reforms was "to define the authority the justice ministry exercises over the judges".

But Tshisekedi's party on Monday lambasted the proposals as a ploy to "undermine the independence of the judiciary and increase the power of the justice ministry".

Tshisekedi took office in January 2019 in the first peaceful transfer of power in the vast central African nation following 18 years with Kabila at the helm.

Creating the coalition took nine months of arduous talks, and the hybrid remains a seething source of tension.