Colombo (AFP) - A Sri Lankan court Tuesday rejected prosecution demands that the country's police chief and a top defence official face murder charges for failing to prevent the Easter Sunday suicide bomb attacks.

Police Inspector General Pujith Jayasundara and former defence secretary Hemasiri Fernando were represented in court after being arrested last week on charges their negligence led to the attacks that killed 258 people.

State prosecutor Dappula de Livera said their negligence amounted to "grave crimes against humanity" and they should face murder charges, but Colombo magistrate Lanka Jayaratne said there was not enough evidence they failed to act on warnings about the bombings by militant Muslims.

Both men who are undergoing medical treatment at two hospitals and were not present in court. They were represented by lawyers and released on bail, but could still face further charges.

Jayasundara is the most senior police official to be arrested in the 152-year history of the force.

Another nine senior officers have also been named by the attorney general as suspects who should be prosecuted for security lapses over the attacks.

Indian intelligence passed on warnings about the Easter Sunday attacks gleaned from a jihadist in Indian custody, but Sri Lankan authorities did not take the threats seriously.

The first Indian warning was given on April 4, more than two-and-a-half weeks before the bombings, which the Islamic State group said it backed.

Local Muslim groups also alerted police and intelligence units over the threat posed by radical cleric Zahran Hashim, who led the suicide bombings.

The fallout from the attacks has turned into a major political battle.

Jayasundara and Fernando have testified to a parliamentary inquiry that President Maithripala Sirisena failed to follow established protocols in assessing national security threats ahead of the bombings.

They also alleged that Sirisena -- who is also minister of defence as well as law and order -- did not take the threats seriously.

Sirisena insists he had no warning of the attacks and has ordered police not to co-operate with the inquiry.