More than a dozen members of Islamist groups detained under former president Hosni Mubarak for allegedly trying to kill top Egyptian officials were released on Monday by presidential pardon.

Former deputy of state security Fouad Allam voiced concern about the decree, demanding more details from President Mohamed Morsi on the reasons behind his decision.

"Members of Islamic group had particular beliefs that pushed them towards committing these crimes, if they're released there must be a guarantee that their ideas have changed," Allam said.

Allam emphasised that if this could be guaranteed, he was an advocate of release, citing the case of Aboud El-Zomor, accused of killing late president Anwar El-Sadat.

Meanwhile Mohamed Zarei Chairman of the Arab Organization for Penal Reform applauded Morsi's decision, describing it as a positive step. He pointed out that the pardon decree is a protocol adopted by any president following a revolution in an attempt to declare "a start of a new era."

Zarei further called for Morsi to "do what it takes to ensure that mistakes that have been committed earlier by Islamic groups are not repeated."

The 1990s saw a rise of militant political Islam; the most notorious attack was the Luxor massacre in 1997 where tens of tourists were killed at the hands of Al-Gamaa Al-Islamiyya.

Morsi's decree has met with approval. However many are sceptical regarding the reasons behind the release of specific people while others remain imprisoned.

Human rights lawyer Gamal Eid told Ahram Online that he was happy with the decision, adding however that "civilians facing military trials should be released as well as they are facing unfair trials."

Lawyer and activist Ragia Omran described the committee appointed by Morsi to look into releasing political prisoners as lacking transparency.

"There are people who have been suffering from health deterioration and were not granted release," said Omran during an interview on private TV channel ONTV.  

On 19 July Morsi also ordered the release of 572 citizens who had been detained by military authorities since last year's Tahrir Square uprising. Not all have been released however.