The International Criminal Court's cases against Kenya's president and deputy will go ahead, the prosecutor said on Thursday in a statement released hours before the Kenyan parliament votes on withdrawing from the court's jurisdiction.
Chief prosecutor Fatou Bensouda also said relatives of witnesses had been continually approached with bribes and threats to disclose the whereabouts of witnesses in the cases against President Uhuru Kenyatta and deputy William Ruto, who are accused of orchestrating violence after elections in 2007 in which 1,200 people lost their lives.
The two are scheduled to go on trial in The Hague soon - Ruto's trial is set to open next week - despite Kenya's efforts to have the cases dropped or moved closer to home.
"The judicial process is now in motion at the International Criminal Court. Justice must run its course," Bensouda said in a video posted on the court's website.
"Witnesses have gone to great lengths to risk their lives and the lives of their relatives to support our investigations and prosecutions," she added.
Kenya's parliament began debating a motion on Thursday afternoon to withdraw from the Rome Statute that underpins the International Criminal Court.
"I am setting the stage to redeem the image of the Republic of Kenya," Aden Duale, majority leader from Kenyatta's Jubilee coalition, told parliament in a televised session laying out the motion.
Even if Kenya does vote to withdraw, its departure from the first permanent international criminal court would take at least a year and would have no effect on cases already in train, Fadi El Abdallah, the court's spokesman, said on Wednesday.
"It's not possible to stop independent judicial and legal proceedings via a political measure," he said.
The Kenyan president's spokesman was not immediately available for comment, but Ruto's lawyer said he would continue to cooperate with the ICC.
"The deputy president has and will continue to cooperate with the court," said Karim Khan, Ruto's counsel before the ICC.
"He wants to clear his name from this nonsense that's being bandied about."
Khan described as "offensive" Bensouda's claim that the relatives of witnesses against Ruto had been intimidated and said she was trying to divert attention from her office's "amateurish" investigation.
"To seek to create a fog of mystery around the inadequacies of her office by alleging witness intimidation is to distort the truth in hideous fashion," Khan said.
He would not comment on whether Ruto supported the motion on withdrawal from the ICC.
Kenya has long campaigned against the trials taking place and has rallied support from other countries in Africa. Kenya has asked the ICC to refer its case against Kenyatta back to the east African country, a move that has been backed by other African Union nations.
The African Union has previously accused the ICC of selective punishment by primarily targeting Africans.
Kenyan officials concede the country has not in the past had the ability to try suspects accused of crimes against humanity, but say its reformed judiciary now does. The ICC has rejected attempts to have the cases moved back to Kenya.
Jakoyo Midiwo, deputy majority leader of the opposition in parliament, criticised the action to pull Kenya out of the ICC, saying the opposition would vote against the motion, which "has divided the country down the middle".
The 2007 violence erupted after supporters of former prime minister Raila Odinga of the Luo ethnic group claimed that former president Mwai Kibaki, a Kikuyu, had stolen victory in the presidential poll.
At the time, Ruto, a Kalenjin, was a key ally of Odinga. Attacks on Kikuyu supporters of Kibaki triggered a bloody cycle of retaliatory attacks against Kalenjins and Luos.
Activists greeted the news of Thursday's parliamentary vote with dismay.
"This motion to leave the ICC is a significant setback for a country that once proudly ratified the Rome Statute in 2002," said William Pace, convener of the Coalition for the ICC, a pressure group.
"In the long run, the promoters of this action are hurting the reputation of Kenya as a nation that supports international human rights and the rule of law."
The trial against Ruto starts on September 10 in The Hague, while Kenyatta's is scheduled to open on November 12.