Image copyright AFP Image caption The two German hostages were reportedly seized at gunpoint in April, from a yacht between Malaysia and the Philippines

A Philippines-based militant group has threatened to kill two German hostages it captured in April.

Abu Sayyaf demanded a ransom and an end to German support for the US-led coalition against Islamic State (IS), a monitoring service called SITE reports.

Abu Sayyaf has proclaimed allegiance to IS, a hardline Islamist group that has seized large areas of Iraq and Syria.

Germany said it had "heard about the report" but refused to withdraw support for US action against IS.

A German foreign ministry spokeswoman said that threats were "not an appropriate way to influence our policy in Syria and Iraq".

She added that there would be no change to the existing German strategy, which consists of logistical support and military supplies for Kurdish peshmerga fighters battling IS militants in Iraq.

Abu Sayyaf has been active since the early 1990s.

It is a small but violent Islamist militant group which operates in the southern Philippines.

It is considered a "foreign terrorist organisation" by the US, and has been blamed for attacks including beheadings.

It is also known to kidnap foreign and local hostages for ransom.

The group claimed responsibility for the 2004 SuperFerry 14 bombing, the Philippines' deadliest terror attack in which 116 people were killed.