The Pentagon announced in a statement Thursday there are now "more than" 500 US troops on the ground in Somalia.
A significant increase from early 2014 when roughly two dozen troops arrived for the first time since 1993 and the Black Hawk Down incident.
US Africa Command says there have been 28 airstrikes this year, mostly from drones against al-Shabaab, long considered the greatest terror threat in Africa.
At a press conference Thursday at the Pentagon, a top defense official denied any "ramp-up."
"I do not believe necessarily there's a ramp-up," said Lt. Gen. Kenneth F. McKenzie, Jr., director of the Pentagon's Joint Staff when asked about the spike in airstrikes in Somalia. "It's the density of targets is such that now there's some of opportunities to do those strikes."
The US military recently conducted six straight days of airstrikes in Somalia from last Thursday to Tuesday.
Last month, al-Shabaab was blamed for a truck bombing in Somalia's capital, Mogadishu which killed over 300 people.
The head of the Pentagon's joint staff said there's no link between the fall of the ISIS capital Raqqa last month, and the first airstrikes against ISIS in Yemen and Somalia.
Earlier this month, the US conducted the first airstrikes against ISIS in Somalia.
McKenzie also denied the increase of hundreds of additional troops in Somalia as a "build up," but just a "flow of forces in and out" of the country.
In addition to Somalia, the US military has conducted over 100 airstrikes against Al Qaeda in Yemen, including the first strikes against ISIS in Yemen last month.