The state department says its embassy in the Yemeni capital Sanaa will stay closed "because of ongoing concerns".
The US closed 19 diplomatic missions in the Middle East and Africa last Sunday in response to what it said was a threat of a terrorist attack.
The consulate in the Pakistani city of Lahore, which closed after a separate threat, will also not reopen yet.
"We will continue to evaluate the threats to Sanaa and Lahore and make subsequent decisions about the reopening of those facilities based on that information," said spokeswoman Jen Psaki.
"We will also continue to evaluate information about these and all of our posts and to take appropriate steps to best protect the safety of our personnel, American citizens travelling overseas, and visitors to our facilities."
US embassies to reopen after terror alert except Yemen
10 August 2013
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The US says 18 of the 19 diplomatic missions recently closed due to security threats will reopen on Sunday.
