A Kenyan woman says she fears for her life after being wrongly identified as a prosecution witness in the International Criminal Court (ICC) trial of Deputy President William Ruto.
Rahab Muthoni has asked for police protection after her photo was circulated on social media.
The court ordered that the identity of the first prosecution witness be protected for her own safety.
Mr Ruto denies organising violence after the December 2007 elections.
He is charged with crimes against humanity over the violence, in which some 1,200 people died and 600,000 were forced from their homes.
ICC chief prosecutor Fatou Bensouda has previously complained that witnesses are being intimidated, leading some of them to withdraw from the case.
On Wednesday, ICC judge Chile Eboe-Osuji warned that anybody revealing the identity of witnesses, or threatening them, would face prosecution.
He was speaking after being told that bloggers were circulating the name and photo of a woman said to be the first witness.
The photo was of Ms Muthoni but a different name was used.
Ms Muthoni lives in Eldoret, Mr Ruto's home town.
She is understood to have been a victim of the post-election violence in which people were attacked and killed because of their ethnic origin.
The first witness at The Hague gave evidence from behind a curtain and with her face pixelated and voice distorted on the court video.
She is being referred to as witness 536.
The BBC's Odhiambo Joseph says the ICC proceedings are being closely followed in Kenya but are dividing the country along political and ethnic lines.
Mr Ruto and President Uhuru Kenyatta were elected in March.
They used their prosecutions by the ICC to bolster their campaign by portraying them as foreign interference in domestic affairs.
Mr Kenyatta, who denies similar charges, is due to go on trial in November.
Radio executive Joshua arap Sang is standing trial alongside Mr Ruto - he too has pleaded not guilty.
Our reporter says that the ICC does have jurisdiction in Kenya, but the situation is complicated as it relies on political goodwill.
Furthermore, parliament recently voted to withdraw from the ICC, which would end the court's jurisdiction in the country.
Witness 536 broke down in court during her testimony on Tuesday.
She is said to have survived the attack on the Kiambaa Church in which about 36 people were burnt to death.
She is a member of the Kikuyu ethnic group, who were targeted by Mr Ruto's Kalenjin community, allegedly at his behest.
Mr Ruto is the first serving official to appear at the ICC.