Relative calm returned to Kenya's main cities after incidents Wednesday morning connected to allegations of electoral fraud by the ruling coalition pending further public pronouncements by opposition leader Raila Odinga.

The opposition National Super Alliance accused the ruling coalition of having hacked the electronic vote-counting system for Tuesday's general election.

But Kenyan Electoral Commission chief Ezra Chiloba denied the accusations and insisted that the system was secure.

Odinga claimed earlier that pro-government hackers introduced an algorithm into the vote-counting system that generated a steady 11-point advantage for incumbent President Uhuru Kenyatta.

The hacks, he said, were executed using the log-in and password of electoral commission telecommunications director Chris Msando, who was found dead 10 days ago with one of his arms hacked off.

Chiloba said that Msando's password had never been revealed to anyone.

With 74 percent of the votes counted, the commission proclaimed Kenyatta the victor over Odinga by a margin of 54 percent to 44 percent.

In Mathare, a Nairobi shantytown, police used tear gas and gunfire to disperse dozens of people who blocked the streets with barricades.

In other parts of the country, such as the western port city of Kisumu, police used tear gas to disperse small groups of protesters who took to the streets after Odinga's claim of fraud.

In Eldoret, one of the cities most affected by the wave of post-election violence of 2007, hundreds of people gathered in the streets to wait.

The Independent Electoral and Boundaries Commission announced that it would investigate allegations made by the opposition, while the government called for calm.