CAIRO (AFP) – The trial of 40 members of Egyptian opposition group the Muslim Brotherhood on charges of money-laundering and financing a banned organisation resumed at a military tribunal on Sunday.

The politically charged trial is taking place amid an ongoing clampdown on the Islamists, with another 28 members of Egypt’s main opposition group arrested in the past two days.

Police arrested 12 Muslim Brothers in Nile Delta towns north of Cairo early on Sunday, having already detained 16 leading members in another swoop in the capital on Friday.

At Sunday’s trial police officers are set to testify that the defendants — mainly businessmen — were involved in financing an illegal group, a charge that in the military court could carry the death penalty.

Rights groups including Amnesty International have voiced opposition to the use of military courts to try civilians, who in this case include the Brotherhood’s number three, Khayrat al-Shater.

The accused were referred to the military court by presidential decree after a number of them were cleared on the same charges by a civil criminal court.

Amnesty said military courts “cannot be seen as independent and impartial tribunals for civilians.”

Hundreds of members of the Brotherhood have been rounded up in recent weeks, many at summer camps the state says are used for training to “destabilise the nation.”

The 16 arrested on Friday, who include senior figures Essam al-Aryan and Mahmoud Hussein, have been ordered held for 15 days pending formal charges being laid against them.

“This is yet another hard blow for us,” the organisation’s number two, Mohammed Habib, told AFP.

The 16 are expected to be charged with belonging to and financing a banned organisation and holding a meeting to plan illicit activities, a judicial source told AFP. The Brothers said they were arrested “at a routine meeting.”

Sunday’s hearing is taking place behind closed doors despite appeals for international observers to be allowed to attend the trial.

“What does the government of Egypt fear? What is it ashamed of doing that it can’t do in broad daylight as the law requires?” former US attorney general Ramsey Clark told reporters last month.

Over the past 10 years, Mubarak’s government has repeatedly relied on military tribunals, which have a more consistent rate of conviction, to try members of Islamist organisations.

The verdicts of military courts have no right of appeal.

Journalists and diplomatic observers were allowed access to military trials in the 1990s, but in recent years they have been open only to lawyers and immediate family members of the accused.

The latest crackdown on the Muslim Brotherhood, which began last December, has especially targeted the organisation’s funding, freezing its assets and arresting prominent businessmen associated with the movement.

The Muslim Brotherhood, which describes itself as a moderate organisation that wants to bring Islamic law to Egypt, has been outlawed since 1954.

The group has more than a fifth of the seats in parliament, but its representatives sit as independents because of its illegal status.