Dhaka - Bangladeshi police on Tuesday killed nine suspected Islamist extremists believed to be planning another mass attack following a deadly café assault earlier this month, the country's police chief said.Police who stormed their hideout said the men belonged to a Bangladeshi group blamed for the Dhaka café attack in which 20 hostages, mostly foreigners, were killed."From police intelligence sources we learnt that they were planning to carry out a major incident. We conducted the operation to foil any such incident," national police chief AKM Shahidul Hoque told reporters."They were wearing the same extremist dress as worn in the Gulshan attack," he said, referring to the upscale neighbourhood where the café was located.One other suspected extremist was shot and arrested during the raid in the capital's Kalyanpur neighbourhood, according to police.Hoque said all 10 were suspected members of the home-grown extremist group Jamayetul Mujahideen Bangladesh (JMB), which local authorities blamed for the Dhaka cafe attack.But a police official said one wounded survivor of the raid had said all of those inside the hideout were followers of the Islamic State group."His name is Hasan. He said they are ISIS members," the police official told AFP on condition of anonymity.He said the 25-year-old was a cook and came from the northern district of Bogra, home to two of the five café attackers.ISIS claimed responsibility for the July 1 attack on the Holey Artisan Bakery in Gulshan.Gruesome images of the carnage were posted on media sites with links to ISIS before the military stormed the café.But Bangladeshi authorities have rejected the ISIS link, saying international jihadist networks have no presence in the world's third-largest Muslim-majority nation.Hoque said the nine killed in Tuesday's operation had no connection with ISIS, even though they were wearing the group's signature black robes and Islamic turbans."We have not found any link with ISIS. They are all local Bangladeshi militants," he said.'Successful operation' Prime Minister Sheikh Hasina thanked the police for a "very successful operation" and said their swift action had saved the country from a "terrible situation"."We don't want Bangladesh to become a sanctuary for the terrorist activities," she said, adding her government would eliminate extremism at all costs.Police said they had cordoned off a five-storey apartment building in Dhaka after suspects threw a small bomb at officers.A gunfight ensued during which cries of "Allahu Akbar" ("God is Great") could be heard through the night as hundreds of heavily armed police and elite security forces sealed off the area.Police said they had found university identity cards at the scene and were checking whether they were genuine.Three were from the North South University (NSU), which hit the headlines when seven students were convicted and jailed for the killing of an atheist blogger.Two of the Gulshan café attackers were former students of NSU."We are now checking whether these university ID cards are genuine or they just used the cards to rent the flat," deputy commissioner of Dhaka Metropolitan Police Masud Ahmed told AFP.Bangladesh is reeling from a wave of deadly attacks by Islamist extremists.Days after the cafe siege, gunmen attacked the country's largest Eid prayer rally where about 250 000 people were marking the end of Ramadan, killing at least three people.Some 80 secular activists, foreigners and members of religious minorities have been killed since 2013, with ISIS and the South Asian branch of al-Qaeda claiming responsibility for many of those attacks.The government and police, however, say home-grown extremists are responsible.They have launched a nationwide crackdown, arresting more than 11 000 people. Among them were over a dozen suspected extremists including one of JMB's regional heads.