A top US envoy has dismissed as "absurd" a reward of 10 camels for information about President Barack Obama's hideout by Somali militants.
The Al Qaeda linked group offered chickens for information about US Secretary of State Hillary Clinton.
Johnnie Carson became the first top US official in two decades to visit Mogadishu over the weekend.
When asked about Al Shabaab's offer at a news conference, the assistant secretary of state for African affairs said: "The question is so absurd it does not deserve a response."
He said his trip to Mogadishu, which lasted a matter of hours, was to note the "significant progress" made against Al Shabaab.
However, the al-Qaeda group still controls much of the country.
After the US put bounties on the heads of al-Shabab commanders, senior militant official Fuad Muhammad Khalaf announced:
"Whoever reveals the hideout of the idiot Obama will be rewarded with 10 camels, and whoever reveals the hideout of the old woman Hillary Clinton will be rewarded 10 chickens and 10 roosters," he said after Friday prayers.
Mr Carson also announced that the US would impose sanctions on anyone standing in the way of the political process now under way.
"The kind of action we must take against spoilers range from visa sanctions totravel sanctions to asset freezes," he said.