Kenyan lawmakers have traded blows and the deputy speaker had water thrown on her amid a chaotic parliamentary session called to push through a tough new security bill.

Opposition MPs shouted and ripped up copies of the bill, warning that Kenya was becoming a "police state".

Four lawmakers were assaulted and another two engaged in a fist-fight.

Parliamentary officials adjourned the debate twice, only for the chaos to continue when it resumed a third time.

The government says it needs more powers to fight militant Islamists threatening Kenya's security.

TV feed cut

The al-Qaeda-linked al-Shabab group has stepped up its military campaign in Kenya, killing 64 people in two attacks in the north-eastern Mandera region since last month.

At one point, live television broadcasts of the debate were cut as the session degenerated into chaos, reports the BBC's Emmanuel Igunza from outside parliament.

A group of pro-government MPs accosted opposition senators who were in the public gallery and tried to eject them, he says.

In the ensuing commotion, one of the senators had his shirt torn, while outside the parliamentary chamber an opposition and pro-government MP threw punches at each other, he adds.

Opposition MPs threw water on Deputy Speaker Joyce Laboso and she ordered two of them to be thrown out, our reporter says.

Earlier, opposition MPs chanted "No way" and "The struggle continues" as they tore up copies of the bill.

There is a heavy police presence around parliament, after activists called for #OccupyParliament protests to show their opposition to the bill, our correspondent says.

MPs were recalled from their Christmas break to approve changes to the bill passed last week.

The bill was denounced by the opposition as draconian and they fear that the proposed amendments will make it even worse.

It gives the security and intelligence agencies the right to detain terror suspects for up to one year, to tap communications without court consent and requires journalists to obtain police permission before investigating or publishing stories on domestic terrorism and security issues.

President Uhuru Kenyatta has defended the bill, saying it is important for the country's security needs.