Dhaka - As many as nine gunmen attacked a restaurant popular with foreigners in a diplomatic zone of the Bangladeshi capital Dhaka on Friday night, taking hostages, killing two officers and wounding at least 26 people in a gun battle with security forces, authorities and a witness said.Police said the two officers died at a hospital after being wounded in the exchange of gunfire with the attackers, who also hurled bombs. Ten of the 26 wounded were listed in critical condition, six of whom were on life support, according to hospital staff, who said the injuries ranged from broken bones to gunshot wounds. Only one civilian was among the wounded.A huge contingent of security forces cordoned off the area around the Holey Artisan Bakery in Dhaka's Gulshan area. A local resident Lutful Amin told the AP he heard several explosions, the last of which went off around 22:45.The Islamic State group's Amaq News Agency said "Islamic State commandos" carried out the restaurant attack, according to the SITE Intelligence Group, which monitors jihadist activity online. Bangladesh authorities did not immediately respond to the claim, but in the past have denied that the extremist group has a presence in the country. The USState Department said it had seen the ISIS claim, but could not confirm its authenticity.'Derailed youths'The head of the elite anti-crime force, Rapid Action Battalion, told reporters Friday night that they were working to save the lives of the people trapped inside the restaurant. The hostages included an unknown number of foreigners."Some derailed youths have entered the restaurant and launched the attack," Benazir Ahmed said. "We have talked to some of the people who fled the restaurant after the attack. We want to resolve this peacefully. We are trying to talk to the attackers, we want to listen to them about what they want.""Our first priority is to save the lives of the people trapped inside," Ahmed said. He would not say how many people were being held hostage.At least 35 people, including about 20 foreigners, were still trapped inside the restaurant, according to kitchen staffer, Sumon Reza, who was among more than 10 people who managed to run to the rooftop and escape.He said the attackers chanted "Allahu Akbar" (God is Great) as they launched the attack around 21:20 on Friday, initially opening fire with blanks.Among the hostages was a businessman and his wife and two children, according to his uncle Anwarul Karim."My nephew Hasnat Karim called me and said he was inside with his family. He told me, 'Please save us, please!' And he hung up," he said. "We do not know what is going on there."Obama briefedIn Washington, a White House official said President Barack Obama was briefed on the attack by his chief counterterrorism adviser Lisa Monaco. The president asked to be kept informed as the situation develops, said the official, who was not authorised to speak publicly about the president's meetings.State Department spokesperson John Kirby says the US is in contact with the Bangladesh government and has offered its assistance to bring those responsible to justice.He said all official American personnel are accounted for with no injuries reported, and the department is working with local authorities to determine if any US citizens and locally-employed staff were affected.Bangladesh, a traditionally moderate Muslim-majority nation, has recently seen an upsurge in militant violence. Nearly two dozen atheist writers, publishers, members of religious minorities, social activists and foreign aid workers have been slain since 2013 by attackers wielding machetes. The frequency of attacks has increased in recent months. On Friday, a Hindu temple worker was hacked to death by at least three assailants in southwest Bangladesh.The attacks have raised fears that religious extremists are gaining a foothold in the country, despite its traditions of secularism and tolerance.Prime Minister Sheikh Hasina's government has cracked down on domestic radical Islamists. It has accused local terrorists and opposition political parties - especially the main opposition Bangladesh Nationalist Party and its Islamist ally Jamaat-e-Islami - of orchestrating the violence in order to destabilize the nation, which both parties deny.The Islamic State group and al-Qaeda affiliates have claimed responsibility for many of the attacks, but the government denies that either group has a presence in the country.