"On Sunday, August 11, the Department of State will reopen 18 of the 19 embassies and consulates that were closed recently," Psaki said in a statement.
America had closed some two dozen embassies and consulates since August 4 as a precaution after it intercepted al-Qaeda's most serious threat in recent years to target its embassies.
"Our embassy in Sanaa, Yemen will remain closed because of ongoing concerns about a threat stream indicating the potential for terrorist attacks emanating from al-Qaeda in the Arabian Peninsula," she said.
"Our consulate in Lahore, Pakistan, which closed on Friday due to a separate credible threat to that facility, will also remain closed," Psaki said.
She said the US would continue to evaluate the threats to Sanaa and Lahore missions and make subsequent decisions about the reopening of those facilities.
The US will also continue to evaluate information about all of its posts and to take appropriate steps to best protect the safety of our personnel, citizens travelling overseas and visitors to its facilities, Psaki added.
On August 4, the US initially closed 22 diplomatic posts for the day and later extended closure of 19 missions till August 10.
The State Department last week also issued a worldwide travel alert warning Americans that al-Qaeda may be planning attacks in August, particularly in the Middle East.