Riot police have deployed in Kenya's capital as anti-corruption protesters took part in a banned demonstration.
The protesters want the vice-president to resign
"Our money, our money!" thousands of protesters shouted in central Nairobi demanding the vice-president and head of civil service step down.
They, along with three ministers who have already resigned, were named in a graft report which has rocked Kenyans.
One of those ministers, Chris Murungaru, has appeared in court on Friday morning to be charged.
Mr Murungaru, who was national security minister, pleaded not guilty to refusing to declare his assets before the country's Anti-Corruption Commission.
He says it infringes on his human rights.
The charge carries a maximum sentence of three-years in prison.
He is the first former minister to be charged in connection with a multi-million dollar scam, known as the Anglo Leasing affair, which involved hundreds of millions of dollars of government contracts being awarded to a phantom firm.
The three ministers who have already resigned as well as Vice-President Moody Awori, who is under heavy pressure to follow suit were named in a report written by the former anti-corruption investigator, John Githongo.
All four have declared their innocence.
Protesters in Nairobi also called for the vice-president to go now.
"Awori must go. Awori must go," the crowd shouted.
A parliamentary committee has returned from a visit to the UK where it met Mr Githongo to tell reporters that it has strong evidence implicating senior officials.
Uhuru Kenyatta, who led the team, said the evidence revealed a "mafia" like system involving top businessmen and politicians.
"What Kenyans need to demand is the complete dismantling of a corrupt system, a system that corrupts even those who claim they are incorruptible," the son of the country's founding president told reporters.
MPs are demanding that parliament, which has been in recess since December, be recalled so they can discuss the allegations.
Earlier this week, Kenyan police ordered 20 senior politicians and officials not to leave the country until investigations were concluded into a second scandal, the so-called "Goldenberg" affair, in which millions of dollars were paid for non-existent exports of gold and diamonds.
President Mwai Kibaki was elected in 2002 on a pledge to fight the corruption which had characterised the previous administration of Mr Moi, who was in power during the Goldenberg affair.