Asia's most vicious terrorist group has set a deadline of 2pm Monday (Thailand time) to behead at least one of three foreign and one Filipina hostages it holds in the southern Philippines.
Abu Sayyaf (Bearer of the Sword), founded by a brother-in-law of Osama bin Laden and now pledging brotherhood with the Islamic State, has demanded a ransom of 300 million pesos each (225.2 million baht; US$6.4 million) to spare the four.
They have been held in the southern Philippines since last Sept 21, when they were abducted from a resort on scenic but isolated Samal Island, Davao del Norte, province. They are believed to be captive at a makeshift Abu Sayyaf camp on nearby Jolo island.
The hostages are Canadian mining consultant John Ridsdel, 68; fellow Canadian Robert Hall, 50, and his girlfriend Marites Flor, and Kjartan Sekkingstad, the Norwegian manager of the resort where they were abducted.
Abu Sayyaf, which has beheaded or shot dead many such hostages in the past, actually extended the death-threat deadline and reduced the ransom demand over the past month. While the group's demands, made on video, have not been entirely clear, it appears they are threatening to kill one of their hostages Monday.
Jolo is a stronghold of Abu Sayyaf. The group, as a news agency put it, is known for bombings, beheadings and kidnappings.
In the latest video, the captives, with machetes held to their necks, asked their families and governments to pay the 300-million peso ransom. This was less than the demand for a billion pesos each that the militants demanded last year.
Abu Sayyaf kidnappers released a brutal video on April 15 as a "final warning" to pay a ransom, roughing up and threatening Canadian Robert Hall with a knife, and assaulting fellow Canadian John Ridsdel (centre).
"This is already an ultimatum", the masked militant leader said. "We will certainly behead one of these four", he added, setting the execution for 3pm Philippines time.
In addition to the group threatened for death Monday, Abu Sayyaf units hold four other important groups of foreign hostages, captured in the past month.
On March 26, the group boarded a cargo ship and abducted 10 Indonesian sailors. A week later, Abu Sayyaf kidnapped four Malaysian sailors from another ship. And on April 15, the terrorist group abducted four other Indonesians in another incident.
Three is no doubt the beheading threat is serious. While Abu Sayyaf has been a vicious group for 25 years, it has recently stepped up its bloody acts.
Last week, it beheaded two Filipino hostages, guards at a local sawmill that the group declared were "spies". Gruesome video and photos were posted to the internet documenting the murders of Makol "Macky" Hanobas and Tado Hanobas.
Last Friday, the group sent more bloody video and images to local media showing, close-up, the decapitation of another Filipino man, Robert Pepito, also an alleged "spy".
Abu Sayyaf also claimed on April 16 it had shot down a Philippines army OV-10 observation plane, and provided video of that, as well.
Abu Sayyaf was funded by Osama bin Laden and formed by his brother-in-law in 1992. Since then, Filipino and allied anti-terrorism forces have whittled away at the group's leadership but have been unable to stamp it out. (File photo)
Little has been noted, however, of a major development in Abu Sayyaf's evolution from al-Qaeda subsidiary to the combination terrorist-extortion group it has become.
Last week, on April 19, Abu Sayyaf announced allegiance to the Islamic State, becoming by far the largest and most important Asian terrorist group to align with the Mideast-based "caliphate" leader Abu Bakr al-Baghdadi.
Abu Sayyaf said Isnilon Totoni Hapilon, known as the main leader of the group, is its official "appointed leader". He came to prominence in 2001 when he headed a team that kidnapped 20 people including three US citizens from the Dos Palmas Resort, Palawan province. Of the three, only a woman, Gracia Burnham, was rescued alive.
The US indicted Mr Hapilon for terrorism, and has posted a reward of $5 million for anyone turning him in. The Philippines is offering a large, proportional reward as well.
Alan Dawson has covered terrorism in Southeast Asia since the Vietnam war.