Thousands of documents that reveal in chilling detail orders from Muammar Gaddafi's senior generals to bombard and starve the people of Misrata have been gathered by war crimes investigators and are being kept at a secret location at the besieged Libyan port.

The vital documents will form damning evidence in any future war crimes trial of the Libyan leader at the international criminal court. The court's prosecutors are expected to travel to the city to view the documents once the daily bombardments have ceased.

One document shows the commander of Government forces instructing his units to starve Misrata's population during the four-month siege.

General Youssef Ahmed Basheer Abu Hajar, states bluntly: "It is absolutely forbidden for supply cars, fuel and other services to enter the city of Misrata from all gates and checkpoints." Another document instructs army units to hunt down wounded rebel fighters, in direct violation of the Geneva Conventions.

Plans to bombard the city and terrorise the population are also in the archive, say investigators, who also claim they have a message from Gaddafi ordering that Misrata be obliterated and the "blue sea turned red" with the blood of the inhabitants.

The documents are expected to form a crucial element of any trial against Gaddafi, his son Saif al-Islam and his intelligence chief Abdullah Senussi if, as is expected, ICC judges confirm indictments for war crimes and crimes against humanity that are demanded by its chief prosecutor, Luis Moreno-Ocampo.

They represent a landmark in international justice because no significant war crimes trial in the short history of international courts has had access to documents directly implicating the lead players of committing war crimes.

"From what we have here, the case is already proved," Khalid Alwafi, a Misrata war crimes investigator, said. The documents have yet to be revealed to the ICC, according to the 60-strong team of Libyan lawyers who brave daily shelling to collect evidence from the city. "We are ready to show them to the ICC," said Alwafi.

The documents were saved when lawyers supporting the rebellion told protesters who broke into army bases and police stations to protect the buildings against arson. In other rebel-held areas such buildings and their contents have been destroyed.