An editorial on Saturday said: "Our Government and that of the United States must hunt down these cowardly attackers and speedily bring them to book."

It added that security arrangements in any "risky places" had to be tightened in case Friday's "morbid success may just egg on these murderers".

The blast, near the US embassy on Friday, killed about 100 people.

Minutes later there was a similar explosion in the Tanzanian capital, Dar es Salaam.

The Nation said it was fairly clear that whoever was responsible must have a score to settle with the US.

Its front page carried a picture of bloodied Kenyan trade minister, Joseph Kamotho.

It also quoted unnamed US and Kenyan security sources as saying a lone suicide bomber had blown himself up in the blast, but also carried a picture of "a suspect" being led away by security guards.

The Nairobi-based East African Standard's front page headline was "Terrorists hit Nairobi".

Both newspapers reported different versions of how many were involved in carrying out the attacks on the US.

The East African Standard's story quoted an unnamed police officer saying two people had been arrested by police minutes after the blast and they had three bombs "two of which exploded, but the third did not".