Seven Russian mercenaries have been killed by ISIS-linked militants in Mozambique - including four who were shot and then beheaded.

The Russians, fighting for the shadowy state-affiliated Wagner Group, were killed in two separate attacks last month, according to sources in the Mozambique military.

Both attacks were ambushes in Mozambique's northern Cabo Delgado state, where ISIS first announced its presence in June this year.

ISIS militants in Mozambique (file image) killed seven Russian mercenaries in two separate attacks last month, including four who were ambushed, shot and then beheaded

ISIS first claimed a presence in northern Mozambique in June when it said it killed several government troops and stole a cache of weapons (pictured)

The second attack, on October 27, saw Russian fighters attacked alongside troops from the Mozambique Defense Armed Forces (FADM).

A source told the Moscow Times that ISIS militants placed barricades across the road then began firing on the convoy.

Four Russian soldiers were shot dead at the scene and then beheaded, according to the source, while a fifth was shot and wounded and later died in hospital.

Mozambique media reports that 20 FADM troops were also killed in the same attack.

Another, previously unreported, attack happened on October 7 and saw two Russian mercenaries shot dead in the same province.

Again, the attack was the result of an ambush and also involved FADM troops, though it is unclear if any of them were killed or how many were killed.

Russia has been supplying arms and military equipment to Mozambique to help in its fight against Islamist insurgent groups since signing a pact in early January 2017.

However, the deal did not stipulate the supply of fighters and as recently as October 8 Moscow denied it had any troops stationed in the country.

Russia has been providing military support to Mozambique to fight local Islamist groups since 2017, but as recently as October this year denied having any troops in the country (pictured, Russian foreign minister Sergey Lavrov shakes hands with Mozambique leader Jose Pacheco)

Wagner fighters are not technically Russian soldiers as they are employed by a private company and not the state, but the firm's owner Yevgeny Prigozhin has close links to Putin and Wagner is also known to recruit from Russia's GRU.

Until this year they had largely been fighting against a local Islamist group called Ansar al Sunnah, which is trying to depose the government and establish an Islamist state in its place.

The group is known locally as al-Shabaab, but has no ties with the Somali terror group of the same name, and few known links with any group outside the country.

ISIS first announced its presence in Mazmbique in June in a statement released by its Central Africa Province group, which is also active in the DRC.

The terror group's media arm said 'several' Mozambique soldiers had been killed in the attack, while weapons and rockets were seized 'as spoils'.

Since then it has claimed a steady string of attacks, largely targeting Christian settlements and military bases in the country's north, near the border with Tanzania.