The hawkish former UN ambassador held his notepad in such a way that the handwritten line was clearly visible, but did not mention plans to deploy US forces to the neighbouring country during his news conference on Monday.
Mr Bolton announced sanctions on Venezuela’s state-owned oil company, PDVSA, designed to ratchet up pressure on embattled president Nicolas Maduro amid an ongoing crisis in the Latin American nation.
Donald Trump was the first to recognise national assembly leader Juan Guaido as interim president following his assertion of legitimacy last week. The UK and a string of other countries followed suit in backing the 35-year-old.
Sanctions to block $7bn (£5.3m) in PDVSA’s assets and $11bn (£8.4bn) in exports will mean Mr Maduro can “no longer loot the assets of the Venezuelan people”, Mr Bolton said during the briefing.
The Pentagon has not announced any plans to send US troops to Colombia. When asked to explain the words in Mr Bolton’s notepad, the White House said that “as the president has said, all options are on the table”.
Colombia said it could not explain the provocative note. Foreign minister Carlos Holmes said he did not know the “importance and reason” for Mr Bolton flashing it and added that Colombia planned to continue “acting politically and diplomatically” in relation to its neighbour.
Bogota has recognised Mr Guaido’s claim to the presidency.
Mr Maduro described the fresh sanctions as “criminal” and accused the US of robbing Venezuelans of oil wealth that was rightfully theirs. He told Mr Trump during a televised address to take his “hands off Venezuela”.
"We will provide the reciprocal and convincing response needed to defend Venezuela's interests in due time," he added, pledging to defend Citgo, PDVSA's US refining subsidiary, which he accused Washington of trying to steal.
Falling oil revenue as a result of the restrictions may hamper Caracas' ability to import basic goods like food and medicine, further exacerbating the humanitarian crisis that has gripped the country.
Additional reporting by agencies
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