Washington ( CNN ) -- All but one of the U.S. diplomatic posts closed this week in a sweeping response to fears of a possible al Qaeda attack will reopen on Sunday , the State Department said . The Obama administration closed 19 embassies and consulates throughout the Middle East and North Africa , and issued a worldwide travel alert due to the threat apparently linked to communications between leaders of the terror group . The closures took effect on Sunday . The embassy in Sanaa Yemen , where al Qaeda in the Arabian Peninsula in based , will remain closed due to continued concerns about a possible attack . Separately , the State Department withdrew most of its diplomatic personnel from its consulate in Lahore , Pakistan , on Thursday , citing a `` separate credible threat '' and warned U.S. citizens against travel to Pakistan . Diplomatic personnel were moved to the capital , Islamabad . The Lahore facility also will remain closed . `` 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 , '' State Department spokeswoman Jen Psaki said in a statement . `` 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 traveling overseas , and visitors to our facilities , '' she added . One U.S. official said there was no link between the broader terror threat and the reason for the action taken in Lahore . However , the official said it does n't rule out a possible link to al Qaeda . Most of al Qaeda 's core leadership is believed to reside in Pakistan and Lahore known to be home to other extremists sympathetic to the group . Response to terror threat scrutinized : Did U.S. go too far ? No U.S. diplomatic posts in Pakistan were closed as a result of the wider warning inked to al Qaeda . Read more : Yemen says it foiled al Qaeda plot . In that case , CNN previously reported U.S. officials intercepted a message between al Qaeda leader Ayman al-Zawahiri and a top ally in Yemen , Nasir al-Wuhayshi , telling him to `` do something '' -- an inference to a terror plot . Now , two U.S. officials tell CNN that in his communication with Zawahiri , Wuhayshi , who is the leader of Al Qaeda in the Arabian Peninsula , laid out a plan for a plot and then Zawahiri acknowledged the communication . Wuhayshi , the officials said , was not asking for permission from Zawahiri -- but rather informing him of his plans . This scenario -- that Wuhayshi presented Zawahiri with a plan -- was first reported Friday in the Wall Street Journal . CNN has also learned that the al Qaeda leaders communicated via some kind of encrypted messaging system , with multiple points of entry to allow for various parties to join in . Asked about his assessment of the terror group in light of the latest threat , President Barack Obama reiterated his conclusion that its core blamed for 9/11 is `` on its heels . '' But he restated that al Qaeda and other extremist groups `` have metastasized '' into regional organizations that can still threaten U.S. interests , including embassies . `` And that 's exactly what we are seeing right now , '' Obama said , noting that anti-terror efforts are an ongoing process . `` We are not going to completely eliminate terrorism . What we can do is to weaken it and to strengthen our partnerships in such a way that it does not pose the kind of horrible threat that we saw on 9/11 , '' he said . The origin of the Pakistan threat was not clear but a separate official said it was `` conceivable '' Lashkar-e-Tayyiba was involved . Lahore is well-known as a base for that group , which is considered a terrorist organization by the United States . Journalist Annabel Symington in Islamabad contributed to this report .
State Department says 18 diplomatic posts will reopen on Sunday . Facilities in Yemen and Lahore , Pakistan , will stay closed for now . No link seen between the Pakistan threat and another one by al Qaeda that forced the wider closures . NEW : Obama says `` we are not going to completely eliminate terrorism ''