Somali Islamist militants have threatened attacks in east Africa and the United States, warning President Barack Obama he would hear "shocking news" as punishment for a U.S. missile strike that killed the rebel group's leader last week.
Al Shabaab made the threats late on Monday, hours after launching twin attacks inside Somalia against African peacekeepers and a government convoy. The death toll from those bombings rose to at least 18 on Tuesday, police said.
"Let our mujahideen (fighters) wait for good news. And let Obama wait for shocking news," senior al Shabaab official, Fuad Mohamed Khalaf Shongole, said in a recorded message, promising to avenge the death of Ahmed Godane in a U.S. raid on Sept. 1.
Al Shabaab demonstrated its ability to strike abroad on Sept. 21, 2013, when the group launched an attack on the upscale Westgate shopping mall in Nairobi, Kenya, that killed 67 people.
Godane publicly claimed responsibility for that assault, saying it was revenge for Kenyan and Western involvement in Somalia and noting its proximity to the anniversary of the Sept. 11, 2001 attacks on the United States.
He was also the group's leader in 2010 when a series of bombs it let off in the Ugandan capital Kampala killed 74.
Shongole's message, which was released over the Internet, threatened further attacks in Kenya and Uganda.
"As you have killed (Godane), many Americans will be killed in New York and Washington. This is real. Men have already been prepared," he added.
Somali President Hassan Sheikh Mohamud told state radio he was confident al Shabaab's "lifespan is ending", referring to a campaign launched by African force AMISOM and Somalian forces to drive the militants out of their remaining strongholds.
"We say to the terrorists, your time has ended," he said.
The group was driven out of Mogadishu in 2011 but has continued to hold other towns and tracts of territory. AMISOM and Somali troops regained several towns earlier this year from the group, whose stronghold is south and central Somalia.
Al Shabaab has staged hit-and-run bomb and gun attacks even as it has lost ground, with Monday's strikes coming shortly after the group named a new leader, Ahmad Umar, who is also known as Abu Ubaidah, to replace Godane.
All those killed on Monday came in the first blast, when a car bomb targeted an AMISOM convoy and ripped apart a nearby minibus.
"The bus was carrying over twenty people and only two survived," Major Hussein Ahmed, a senior police officer, told Reuters. "We are afraid the death is higher than that, as some mothers were carrying their babies on their laps."
A nurse at a Mogadishu hospital, Halima Ibrahim, said 25 people were being treated - 16 civilians from the first car bomb and nine soldiers from a second attack on a Somali security convoy. Many were seriously hurt and burnt, she said.
Al Shabaab, which literally means "the Youths", wants to impose its strict version of Islam on Somalia.