RIYADH (REUTERS) - A Saudi blogger jailed last year for publishing an imaginary conversation with Islam's Prophet Muhammad on Twitter walked free early on Tuesday, his friend and a lawyer said, though there was no comment from the government.

Hamza Kashgari fled Saudi Arabia for Malaysia in February last year after his tweets enraged some conservative Muslims and triggered death threats. He was extradited back to the kingdom days later and imprisoned.

"He was freed this morning," the 24-year-old's friend told Reuters, 20 months after the detention, but he declined to comment further. Prominent human rights lawyer Abdulrahman Allahim congratulated Kashgari on his release on Twitter.

Kashgari, a former columnist in the kingdom's al-Bilad newspaper, issued a long public apology after deleting the messages, and his family said he had repented. The authorities did not make any formal charges against him public.

Offences like blasphemy can be punished by death under the strict interpretation of Islamic law enforced in Saudi Arabia, the world's top oil exporter and birthplace of Islam.

Kashgari's tweets addressed Prophet Muhammad on his birthday, saying he "loved the rebel in you" and "loved some aspects of you, hated others". Saudi Arabia's Information Minister Abdul-Aziz Khoja said at the time the tweets had made him weep.

Raif Badawi, another blogger accused of blasphemy, is appealing against his sentence of seven years in prison and 600 lashes imposed this summer, his lawyer Waleed Abu al-Khair told Reuters.

Saudi Arabia also briefly released political rights activist Mohammed al-Bajadi this summer, but returned him to prison days after he was freed.

The kingdom has dismissed criticism of its human rights record from Western countries and campaign groups.

On Monday, the Cabinet issued a statement saying it "works to protect and promote human rights to maintain its identity, culture, gains and care for its citizens, on the basis of adherence to the Holy Quran".