The United States kept Cuba on a black list of alleged state sponsors of terrorism for the 30th year running, the State Department said in an annual report.
Cuba angrily denounced the action as another US attempt to justify its 50-year-old trade embargo on the communist-ruled island.
"Cuba's foreign ministry energetically rejects that such a sensitive issue as terrorism be used for petty political purposes and demands that the government of the United States stop lying," it said in a statement.
The Americas' only one-party communist regime is one of four countries perennially on the black list -- along with Iran, Sudan and Syria -- a distinction that comes with stiff trade sanctions, including blocks from receiving financial assistance from the US.
The report accused Cuba of harboring members of illegal armed groups, including Basque separatist group ETA and Colombian leftist militants FARC, as well as fugitives wanted in US courts.
The US designates both FARC and ETA as terrorist groups.
Additionally, the US found "deficiencies" in Cuba's efforts to uphold international standards for combating money laundering and the financing of terrorist groups.
However, there was no evidence Cuba gave weapons or paramilitary training to militants, and press reports indicated the Castro regime was trying to distance itself from the Basque separatists living there, the department said.
Havana has routinely dismissed the accusations involving the FARC and ETA members lobbed by Washington in its yearly report.
There have been some calls from within the US to take Cuba, already subject to a full US economic embargo since 1962, off the terror list.
They argue that there are no objective criteria to decide which countries should be listed and which should not, and say the eternal blacklisting fails to acknowledge progress in the Caribbean nation and is not productive toward efforts to improve relations between the two rival neighbors.
North Korea was removed from the US list in 2008.
The US also noted Iran "sought to expand its activities in the Western Hemisphere," adding that the "most disturbing manifestation" of this was a failed plot using contacts with a Mexican drug cartel to assassinate the Saudi ambassador to the US.
The report called out the government of Venezuelan President Hugo Chavez for maintaining "its economic, financial, and diplomatic cooperation with Iran as well as limited military related agreements."
Growing antagonism between Washington and Caracas in 2010 led both countries to withdraw their ambassadors.
But the report commended Mexico for remaining "vigilant against domestic and international terrorist threats," including by cooperating on the sting operation that foiled the Saudi ambassador assassination plot.