A senior Kenyan official at the State House has criticised the United States for raising concerns about a new Kenyan law aimed at fighting "terrorism".



Munyori Buku said in a statement on the presidential website that Kenya's new law had checks and balances, unlike US security laws that have created the Guantanamo Bay detention centre and given the US Federal Bureau of Investigation and intelligence officers "a carte blanche in the fight against terrorism and biological warfare".



On Friday, President Uhuru Kenyatta signed the law his government says will help fight terrorism. The president said the law will protect the lives of all citizens. But critics in Kenya have said it will be used to crush dissent by curbing civil liberties.



US State Department spokeswoman Jen Psaki said on Friday said the US was concerned about the move.



"We're...concerned about provisions that appear to limit freedom of assembly and media, and access to asylum for refugees.''



Related: Kenya president signs tough 'anti-terror' law

Kenya's main opposition group, the Coalition for Reforms and Democracy said the real target of the new law was not terrorism but to reintroduce the police state and political hegemony, and would hand the president sweeping autocratic powers.



The controversial measures extend the time police can hold "terror suspects" from the current 90 days to nearly a year, increase sentences and give more powers to tap phones.



Journalists could face up to three years behind bars if their reports "undermine investigations or security operations relating to terrorism," or if they publish images of "terror victims" without permission from the police.



"This is a serious assault on the freedoms that Kenyans are enjoying today. We believe that the amendments are just a way of sugarcoating the bill," said opposition coalition leader Moses Wetangula, referring to minor changes made to the bill.



Inside Kenya's death squads



The developments come days after an Al Jazeera documentary, Inside Kenya's Death Squads, shed light on extra-judidical killings in Kenya, in the name of fighting terrorism. The film featured officers four units of Kenya’s counter-terrorism apparatus, admitting that police assassinated suspects on government orders.

The officers said executions were being sanctioned by officials high up in the government, as high as the State house.



In response, the Kenyan government lodged a complaint with Al Jazeera describing the the documentary as "inaccurate, biased and inflammatory."



In reply, Al Jazeera urged the "Government of Kenya (GoK) not to attack journalists or to curtail freedom of speech, but instead to confront the serious allegations that its agents commit extra-judicial killings."

Munyori Buku's comments also came a day after another attack on civilians along the Kenyan coast close to the border with Somalia.

Gunmen opened fire on a passenger bus on Sunday, but fled without injuring anyone.



The government of the East African nation has faced mounting calls to get tough on terrorism since 67 people were killed last year in an attack launched on the Westgate shopping mall in Nairobi by neighbouring Somalia's al-Shabab.

The armed group has vowed to step up attacks on Kenyan soil in retaliation for Kenya's military presence in Somalia as part of the African Union force supporting the country's fragile government.