The brother of an Iraqi journalist who hurled his shoes at George Bush claimed today that the television reporter was too badly beaten to appear in court, as the speaker of Iraq's parliament reportedly announced his resignation over the issue.

Dargham al-Zaidi said he was told a judge had been to see his younger brother, Muntazer, at the jail where he has been held since throwing his shoes at the US president during a press conference in Baghdad on Sunday. The television reporter – whose actions have made him a star in the Arab world – called Bush a "dog" and said he was angry at the US occupation of his country.

The family went to Baghdad's central criminal court expecting a hearing, Dhargham said, but were told the investigative judge had been to the prison and they should return in eight days. "That means my brother was severely beaten and they fear that his appearance could trigger anger at the court," he said.

Iraqi officials have denied that Muntazar, a 29-year-old reporter for the private Al-Baghdadia TV station, has been injured. Under Iraq's legal system a judge investigates an allegation before recommending whether to order a trial. Initial hearings are often conducted informally rather than in court.

According to Dargham, his brother suffered a broken arm and ribs, as well as injuries to an eye and a leg after being beaten by security officials, and was treated at the Ibn Sina hospital, in Baghdad's heavily fortified Green Zone. Dargham said he did not know whether the injuries happened when Muntazer was being overpowered at the press conference or later.

The journalist faces possible trial under a clause in the Iraqi penal code outlawing "aggression against a president". If convicted, he could be imprisoned for seven to 15 years. Dargham said he was told by the investigating judge that his brother "had co-operated well", but had no other details.

During a press conference marking Bush's farewell visit to Iraq as US president, Muntazer jumped up and shouted: "It is the farewell kiss, you dog". He threw both his shoes at the US leader – a severe insult in the Arab world.

Iraq's parliament erupted into chaos today as MPs debated Muntazer's continued detention. An official in the office of the speaker, Mahmoud al-Mashhadani, said he had resigned after the row, although it was not clear why this had happened.

The US state department said yesterday it would condemn "unnecessary force" used against Muntazer, but it did not know whether any had occurred.

Bush's press secretary, Dana Perino – who was sporting a bruise under her eye after being struck by a microphone stand during the melee – said the president held "no hard feelings" about the incident and accepted it was up to Iraq to decide on any punishment.