Nigeria has begun working on the security and information sharing requirements for the lifting of a US travel ban on prospective immigrants from the African nation, Nigerian Foreign Minister Geoffrey Onyeama said on Tuesday. Speaking at a joint news conference in Washington with US Secretary of State Mike Pompeo, Onyeama said Nigeria was 'blindsided' by the US decision on Friday to add it and five other nations to an expanded version of the US visa ban. The action was issued as part of a proclamation by US President Donald Trump. US officials said the countries failed to meet US security and information-sharing standards, which necessitated the new restrictions. "We've identified all those requirements and we have actually started working on all them," Onyeama said. "It is actually very straightforward and it was very gratifying to come here and meet with US officials and to understand more clearly the reasoning behind it," he said. Nigeria, the most populous nation in Africa, is the biggest country on the list whose citizens will be suspended from US visas that can lead to permanent residency. Eritrea, Kyrgyzstan and Myanmar were also slapped with a similar ban. The US government also will stop issuing "diversity visas" to nationals of Sudan and Tanzania, Trump's proclamation said.