The Islamist militant group al Shabaab on Monday claimed responsibility for the massive truck blast in Somalia over the weekend that left at least 90 people dead.
A spokesman for al Shabaab, which has ties to al Qaeda, said the bombing targeted a convoy of Somali and Turkish forces.
The message also accused Turkey of trying to control Somalia's resources.
The extremist group has regularly carried out bombings during its more than decade-long fight to topple the UN-backed Somali government.
But the government itself said a foreign country was behind the horrific suicide attack at a busy checkpoint near Mogadishu.
In a tweet Monday, Somalia's National Intelligence and Security Agency said, "a foreign country planned the massacre of the Somalis."
The agency didn't name the country it said was involved in the attack, but said it will work with foreign intelligence agencies in its investigation.
Recently, Somalia has become an arena for military and political rivalry between Turkey and Qatar on one side and Saudi Arabia and United Arab Emiretes on the other.
Saturday's attack was the most deadly to hit Somalia since 2017.