Former Bosnian Serb army chief Ratko Mladic has refused to testify after former Bosnian Serb leader Radovan Karadzic called him as a defense witness at his war crimes trial at The Hague.

It was the first time Ratko Mladic and Radovan Karadzic had appeared together in public since the end of the 1990s war in Bosnia.

Denouncing the UN Yugoslav war crimes tribunal as “satanic”, Ratko Mladic said testifying could harm his own case.

Both men deny charges of war crimes and crimes against humanity.

In his case, Radovan Karadzic faces 11 charges, including genocide relating to the Srebrenica massacre in July 1995.

At Tuesday’s hearing, Radovan Karadzic’s lawyer argued that Ratko Mladic was “the one person in the whole world who knows best what happened in the war in Bosnia” and that Karadzic was asking him to do his best to testify and to tell what had occurred.

Ratko Mladic initially refused to take the oath, saying: “Your subpoenas, your platitudes, your false indictments, I do not care one bit about any of it.”

He added: “I do not recognize this hate court. It is a satanic court.”

The judge warned him he could be held in contempt, with a possible jail term of up to seven years.

The session was then adjourned, apparently so Ratko Mladic’s dentures could be retrieved from his cell.

Ratko Mladic has refused to testify after Radovan Karadzic called him as a defense witness at his war crimes trial at The Hague

On the court’s return, the judge advised Ratko Mladic he was not obliged to answer questions if he thought the answers would incriminate him.

Radovan Karadzic then addressed Ratko Mladic in person, saying: “Good morning general, sir.”

Ratko Mladic did answer Radovan Karadzic’s first question – listing the posts and dates of his military career.

But following the second question – Did you ever inform me that prisoners from Srebrenica would be, were being or had been executed? – Ratko Mladic said: “I refuse to testify on the grounds of my health and because it may prejudice my rights as an accused.”

Lawyers representing Ratko Mladic say he suffers from a memory disorder that makes it hard for him to differentiate between truth and fiction.

The judge ruled Ratko Mladic would not be compelled to answer.

Radovan Karadzic read out his remaining questions, but received the same reply.

Ratko Mladic again asked if he could read out a seven-page statement but was refused. He denounced the court again as the session was adjourned.

Radovan Karadzic had been hoping his former ally’s answers would support his claims that the orders to commit war crimes did not come from him.

The key charges facing Radovan Karadzic relate to Sarajevo and Srebrenica.

The siege of Sarajevo lasted for more than three-and-a-half years – starving the capital of food and power.

Radovan Karadzic is alleged to have orchestrated the shelling of Sarajevo, and the use of 284 UN peacekeepers as human shields in May and June 1995.

In the Srebrenica enclave, Bosnian Serb forces overran the UN-defended safe area in the worst atrocity in Europe since the end of World War Two.

More than 7,500 Muslim men and boys were killed.

Ratko Mladic was the general in charge of the troops.

His trial is being conducted simultaneously at the International Criminal Tribunal for the former Yugoslavia (ICTY).

Radovan Karadzic was arrested in Belgrade in 2008 after 13 years on the run.

He had been found living in disguise in Belgrade, under a false name and working as a New Age healer.

Ratko Mladic was on the run for 16 years before being arrested in 2011 in northern Serbia, where he had also been living under an assumed name.

When Bosnia-Hercegovina became an independent state in 1992, Radovan Karadzic declared the creation of the independent Serbian Republic of Bosnia and Hercegovina (renamed Republika Srpska) with its capital in Pale, a suburb of Sarajevo, and himself as head of state.

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