BEIRUT (AFP) — Relatives of suspected members of an Islamist group that battled the Lebanese army last year staged protests on Friday demanding their release from jail.

Hundreds gathered inside Al-Omari mosque in central Beirut after weekly prayers in support of some 300 people arrested after more than three months of deadly clashes between the army and the Al-Qaeda-inspired Fatah al-Islam.

The protesters, among them bearded men and women wearing the niqab Islamic veil who answered a call from the radical Islamist Hizb al-Tahrir group, held up banners saying: "Free these innocents immediately."

Dozens more protesters gathered outside Rumieh prison in eastern Beirut where the prisoners are held, also calling for their release.

"If the prisoners are not freed by the start of Ramadan (early September), more measures will be taken," they warned in a statement, a copy of which was obtained by AFP.

More than 400 people were killed, including 168 soldiers, in the 15-week battle in and around Nahr al-Bared Palestinian refugee camp on the outskirts of the northern city of Tripoli from May to September last year.

Over the past month supporters of the prisoners have held almost weekly protests and the prisoners began a hunger strike on August 4.

The prisoners -- including Syrians, Saudis, Palestinians and Lebanese -- are being held on terrorism-related charges and many face the death penalty if convicted. No date has been set for their trials.

Last week a protest in Tripoli turned violent when demonstrators pelted a member of parliament with stones and bottles