Finland has accused four people of financing Somalia's Al-Qaida-linked Shebab rebels, the authorities said on Wednesday, the first time the Nordic country has brought terrorism funding charges.

The state prosecutor claims the four sent "several thousand euros" to the terrorist group which has been staging a bloody eight-year insurgency in the war-ravaged east African country.

Ugandan police said Sunday that 19 suspected Islamist Shebab insurgents arrested in weekend raids had planned to carry out bomb attacks, as the U.S. embassy said the immediate threat had been "countered".

Police raids on Saturday came two weeks after Ugandan troops, fighting in Somalia, reportedly provided intelligence that helped U.S. special forces kill the Shebab's chief in a devastating air strike.

French intelligence services assisted Washington in the operation that killed the commander of Somalia's Shebab militant group earlier this month, local media reported Saturday.

"France and President (Francois Hollande) supported with intelligence and coordination" a U.S. air strike that killed Ahmed Godane, the commander of the Islamist faction responsible for a string of deadly attacks throughout Somalia, the weekly Le Point magazine said.

U.S. President Barack Obama has ordered a "relentless" war against the Islamic State, and has cited the ongoing intervention in Somalia as a model for intervention in Syria and Iraq.

So drawing on the experience of U.S. operations against Somalia's al-Qaida-linked Shebab rebels, what can the Islamic State expect to face in the coming months and years?

A suicide bomber from Somalia's Shebab insurgents killed at least 12 people and wounded 27 others Monday by ramming a vehicle packed with explosives into a convoy of African Union troops, officials said.

The attack, the latest in a string of killings, comes exactly one week after a U.S. airstrike killed the chief of the al-Qaida-linked Shebab rebels, Ahmed Abdi Godane, prompting threats of retaliation from the extremists.

Three German men were arrested at the weekend when they flew home from Kenya, accused of having joined and fought with Somalia's Shebab Islamist militant group, officials said Monday.

Internationally-funded African Union troops in war-torn and impoverished Somalia have raped women and girls as young as 12 and traded food aid for sex, Human Rights Watch said in a damning report Monday.

"Some of the women who were raped said that the soldiers gave them food or money afterwards in an apparent attempt to frame the assault as transactional sex," the HRW report said.

Somalia's al-Qaida-linked Shebab militants on Saturday announced the appointment of a successor to their former leader who was killed in a U.S. air strike.

The group also vowed to avenge the death of Ahmed Abdi Godane and said they would continue their fight to topple the country's internationally-backed government.

The U.S. missiles that smashed into Somalia's Islamist chief this week ended the life of the one of the world's most wanted men, but not the danger of his Shebab insurgents, analysts warn.

Ahmed Abdi Godane, declared dead by the United States after an air strike earlier this week, was a ruthless kingpin of Al-Qaida's main African affiliate.

The United States said Friday it had killed the chief of al-Qaida-linked Shebab militants in a bombing raid in Somalia which President Barack Obama said could prove a model for an assault on Islamic State jihadists.

The Pentagon confirmed that Ahmed Abdi Godane perished in the raid on Monday in which U.S. drones and manned aircraft rained Hellfire missiles and laser-guided bombs on a gathering of Shebab commanders.