A propagandist for Osama bin Laden was convicted on three charges of war crimes on Monday at Guantanamo Bay, Cuba, and sentenced to life imprisonment, dpa reported. Ali Hamza al-Bahlul, a Yemeni, will immediately begin serving his prison term at the naval base, the Pentagon said after announcing the sentence. Al-Bahlul is only the second detainee tried and convicted under President George W Bush's controversial military commissions. With the completion of sentencing, his case will be subject to automatic review by Court of Military Commission Review. He will be allowed to appeal his conviction in a US federal court. Pentagon prosecutors argued that al-Bahlul, about 40 years old, made videos designed to boost al-Qaeda recruitment and incite suicide bombings, the report said. He was found guilty of conspiracy, providing material support for terrorism and soliciting murder. Al-Bahlul refused to mount a defence and did not allow his military-appointed attorneys to question witnesses or challenge evidence, saying he could only be tried under Islamic Sharia law, The Miami Herald reported. "Go ahead with your trial. And I will continue with my boycott. Do whatever you want," al-Bahlul said, according to the newspaper. Al-Bahlul and bin Laden's driver, Salim Hamdan, also of Yemen, are the only two of the remaining 255 detainees at Guantanamo to be convicted. Hamdan was convicted in August and received a five-and-a-half year prison sentence, which included his time already served. As bin Laden's alleged driver and bodyguard, Hamdan was found guilty of providing military support to terrorism.