Nairobi - Four former Kenyan ministers should be prosecuted for their part in one of the country's biggest corruption scandals involving about $300-million, Kenya's anti-graft body said on Monday.

It did not name names in the statement, which was issued amid mounting political pressure over the slow pace of investigations into the so-called Anglo Leasing affair, which involved state tenders awarded to fictious firms.

The Kenya Anti-Corruption Commission (KACC) said it had made recommendations to the attorney-general to prosecute two ex-finance ministers, one ex-transport minister and one former internal security minister.

The scandal has presented President Mwai Kibaki with his biggest political crisis since his ruling coalition swept to power in 2002 vowing to end rampant corruption.

The scandal claimed its first casualty when Kibaki was forced to drop former powerful security minister Chris Murungaru, who had been demoted to the transport ministry.

It also forced former Finance Minister David Mwiraria and former Justice Minister Kiraitu Murungi to quit in February, a month after details of the case were leaked by former presidential adviser on corruption John Githongo.

Kibaki's government has been at pains to show Anglo-Leasing started under the rule of former president Daniel arap Moi.

Last month, Justice and Constitutional Affairs Minister Martha Karua released a list of 10 sitting and former ministers who were in charge of various ministries when the suspicious contracts were signed.

Outcry over the scam resurfaced two weeks ago when local media reported that KACC director Aaron Ringera asked Githongo to stop his pursuit of the affair. Ringera denied the allegations.