"The sources said Kashgari was accompanied by Saudi officials on his flight to King Khaled International Airport in Riyadh," it reported.
He "will face charges of blasphemy," the sources told the daily.
Kashgari was detained in Malaysia last week after fleeing Saudi Arabia in fear for his life after a Twitter post about the prophet sparked outrage.
Kashgari, 23, was a columnist at the Jeddah-based Al-Bilad newspaper, which announced his sacking following the controversy over his tweets.
Insulting the Prophet Mohammed is considered blasphemous in Islam and is a crime punishable by execution in deeply conservative Saudi Arabia.
"Kashgari is in the hands of Saudi authorities. Thank you our King Abdullah," Tweeted Abdulazeez al-Sahn as soon as news of the journalist's arrest emerged.
Rights groups had earlier warned that deporting Kashgari would be akin to a death sentence and urged Muslim-majority Malaysia to free him.
A group on the online social network Facebook calling itself "The Saudi people demand Hamza Kashgari's execution" has amassed more than 21,000 members.
Referring to the prophet, Kashgari had tweeted: "I have loved things about you and I have hated things about you and there is a lot I don't understand about you.
"I will not pray for you."
Kashgari quickly repented, tweeting: "I have made a mistake, and I hope God and all those whom I have offended would forgive me."
The controversial tweet sparked a frenzy of responses, some 30,000 according to an online service that tracks tweets in the Arab world.
In one Tweet, Abdullah, a lawyer, said that since Kashgari was "an adult... we should accept nothing but implementing the ruling according to Islamic (sharia) law."
Another Tweeter, Saleh al-Ghamdi, was not so harsh. "Brothers, the man has repented. If the prophet himself was here he would have forgiven him and ended this," he wrote.
A committee of top clerics branded Kashgari an "infidel" and demanded his trial in an Islamic court.
Malaysia has no formal extradition treaty with Saudi Arabia and Kashgari's deportation has been condemned by rights groups.
The European Union said it was "deeply disappointed" Malaysia had deported Kashgari and voiced regret that the office of the UN High Commissioner for Refugees had not been granted accesss to him.
"The EU will continue taking all appropriate steps to achieve a positive outcome of Mr Kashgari's case," said Maja Kocijancic, spokeswoman for EU foreign policy chief Catherine Ashton.
Responding to claims that Interpol was involved in Kashgari's deportation, the international police body issued a statement on Monday repeating its denial of any involvement in the case.
"No Interpol channels, its national central bureaus in Kuala Lumpur and Riyadh nor its general secretariat headquarters in Lyon, France, were involved at any time in this case," it said.
Interpol first issued a denial last week of any involvement, saying the arrest of Kashgari took place on a bilateral basis between Malaysia and Saudi Arabia.
But it said on Monday it was repeating its statement because numerous news outlets had either stated or implied that it was involved.
The incident has shone a spotlight on the use of freewheeling Internet social media networks such as Twitter and Facebook in deeply conservative Saudi Arabia.
Top Saudi cleric Grand Mufti Sheikh Abdul Aziz bin Abdullah al-Sheikh has called Twitter "a great danger not suitable for Muslims" and "a platform for spreading lies and making accusations."
But millions of Saudis, including many government officials, have Twitter and Facebook accounts.
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