DR Congo President Felix Tshisekedi on Monday blocked newly-named senators from taking office and called for a probe into corruption that had allegedly stained their election, an official said.
The announcement was made by the acting interior minister, Basile Olongo, after supporters of Tshisekedi's predecessor, Joseph Kabila, swept to victory in last Friday's senatorial elections.
After an inter-ministerial meeting, Olongo said Tshisekedi was "suspending the senators' induction" and postponing elections for provincial governors, due on March 26, until further notice.
He also asked prosecutors to "open inquiries into ingrained corruption" among elected officials.
"Senators and provincial deputies, those who corrupt and those are corrupted... (must be) severely punished," the president was quoted as saying.
The Democratic Republic of Congo's upper house is elected indirectly by the country's provincial assemblies -- a process that critics say is notorious for kickbacks.
Elections that were held in 24 out of the country's 26 provinces -- the vote was postponed in the other two -- handed 84 out of 100 Senate seats to Kabila's Common Front for Congo (FCC) coalition.
That huge majority entitles the FCC to make changes to the country's constitution or pursue legal proceedings against the current head of state.
The FCC also wields a massive majority in the lower house, the National Assembly, after the December 30 elections won at the presidential level by Tshisekedi.
Taking office on January 24 in the first peaceful transition of power in DR Congo since it became independent from Belgium in 1960, Tshisekedi vowed to root out entrenched corruption and improve its record on human rights.
Last week, he issued pardons for an opposition leader and a rights activist jailed during Kabila's 18-year presidency.
But he has otherwise struggled to push ahead with legislative reforms in the face of Kabila's power base.
On Monday, Arthur Ilunga, the prosecutor at the court of appeal in Matadi, in the southwestern region of central Kongo, said three provincial deputies who faced "serious suspicions about corruption" had been arrested.
"The list could lengthen because the investigation is ongoing," Ilunga said. He did not give the name of the three arrested.
Tshisekedi's own party, the UDPS, has come under attack from the grassroots over the vote-buying charges.
The party's interim president, Jean-Marc Kabund, told a rally in Lubumbashi, in the southeast, that 26 UDPS deputies in four provincial assemblies would be handed over to the authories.
"These deputies will be stripped of their posts and replaced by their alternates," he said.