Philippine authorities have detained five suspected Abu Sayyaf militants in connection with the deadly bombing of a cathedral last month. 

The attack on Our Lady of Mount Carmel Cathedral in Jolo town, Sulu province, in the south-west of the country killed 23 people and wounded dozens more. 

The suspects face charges of murder and attempted murder.  In addition to the five detained, the Associated Press reports that several more remain at large. 

National police chief Oscar Albayalde said on Monday that the detainees are suspected of escorting two Indonesians believed to have been behind the attack to a meeting with Abu Sayyaf commander Hatib Hajan Sawadjaan prior to the bombing. 

Authorities have accused Sawadjaan of planning and funding the attack.  Another suspect identified as Kammah Pae is believed to have helped plan the attack but did not take part in its execution. 

'Although he has knowledge about the bombing ... he did not actually participate,' Defense Secretary Delfin Lorenzana told reporters.

Last week, interior minister Eduardo Año said the evidence pointed to an Indonesian man and his wife carrying out the attack. 

'They are Indonesians,' Año, a former military chief, told CNN Philippines' News Night. 'I am certain that they are Indonesians.'

He added, 'There are two foreigners involved in the bombing and they were aided by local Abu Sayyaf who acted as guide, and probably conducted preliminary surveillance prior to the bombing,'

Doubts were raised over the claim by Sidney Jones, director of the Jakarta-based Institute for Policy Analysis of Conflict, who said the authorities did not know who had carried out the attack. 

'There's no evidence! Different officials are saying different things - Malaysians, Yemenis, Indonesians. They actually have no clue,' she told The Jakarta Post. 

The attack has elevated fears of the Islamic State gaining a foothold in the region after it claimed responsibility for the double bombing.