A top Turkish pianist and composer appeared in court on Thursday to defend himself against charges of offending Muslims and insulting Islam in comments he made on Twitter.

Fazil Say, who has played with the New York Philharmonic, the Berlin Symphony Orchestra and others, is on trial for sending tweets that included one in April that joked about a call to prayer that lasted only 22 seconds.

Say tweeted: "Why such haste? Have you got a mistress waiting or a raki on the table?" Raki is a traditional alcoholic drink made with aniseed. Islam forbids alcohol and many Islamists consider the remarks unacceptable.

Prosecutors in June charged Say with inciting hatred and public enmity, and with insulting "religious values". He faces a maximum sentence of 18 months in prison, although any sentence is likely to be suspended.

Say, who has served as a cultural ambassador for the European Union, rejected the charges and demanded his acquittal, said the state-run Anadolu agency.

The private Dogan news agency said the trial was adjourned until 18 February.

The prosecution has caused anger among intellectuals in Turkey and escalated concerns over freedom of expression in the country. Hundreds of his fans, supporters and human rights activists went to the courthouse in Istanbul in a show of solidarity, holding up signs that said: "Fazil Say is not alone," and "Free Art, Free World."

Say, 42, is a strong critic of the government of Prime Minister Recep Tayyip Erdogan, a devout Muslim who has preached conservative values, alarming some secular Turks who fear the government plans to make religion part of their lifestyle.

Some have drawn parallels between Say's case and that of the Russian band Pussy Riot who staged an impromptu punk performance at Moscow's main cathedral in February in protest against President Vladimir Putin and the Russian Orthodox church hierarchy. The three women were convicted of hooliganism motivated by religious hatred, but they insist that their protest was political in nature and not an attack on religion.

Turkey has a history of persecuting its artists and writers, and the European Union has long encouraged the nation to improve freedom of speech if it wants to become a member of the bloc one day.

In a report on Turkey's progress toward membership issued last week, the EU criticised Turkey for "recurring infringements of the right to liberty and security and to a fair trial, as well as of the freedom of expression." It said restrictions on media freedoms and an increasing number of court cases against writers and journalists remained "serious issues".

Turkey's Nobel laureate Orhan Pamuk has been prosecuted for his comments about the mass killings of Armenians under a law that made it a crime to insult the Turkish identity before the government eased that law in an amendment in 2008. In 2007, ethnic Armenian journalist Hrant Dink, who received death threats because of his comments about the killings of Armenians by Turks in 1915, was shot dead outside his office in Istanbul.

On Thursday, Egemen Bagis, the minister in charge of relations with the EU, suggested the case against Say should be dismissed, saying the court should regard Say's tweets as being within "his right to babble". However, he criticised the pianist for "insulting people's faith and values".

The charges against Say also cite other tweets he sent, including one – based on a verse by famous medieval poet and wine-lover Omar Khayyam – which questioned whether heaven was a tavern or a brothel, because of the promises that wine will flow and each believer will be greeted by virgins.

Say has since closed his Twitter account and has said he plans to leave Turkey for Japan. His lawyer said Say had received some death threats.