Cairo, Egypt (CNN) -- American citizens who want to leave Egypt on a U.S. government flight should report to the airport as soon as the nightly curfew ends, according to official Twitter messages from the Department of State Bureau of Consular Affairs. Tweets warning Americans to leave began appearing just before 10 p.m. ET, cautioning that further delay was not advisable. More than 1,900 U.S. citizens and their family members have left Egypt since an evacuation operation began Monday, according to a statement from the U.S. State Department. Evacuation flights had been scheduled to run through Thursday. The State Department said late Wednesday that additional government flights after Thursday are unlikely.
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NEW: State Department warns that evacuation delay is not advisable
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NEW: The department says U.S. citizens wanting to leave Egypt should go to airport after curfew
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1,900 Americans and their families have been evacuated, the department says
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The U.S. Embassy in Cairo remains open to help Americans who want to evacuate
Any @placeholder with out-of-date paperwork could go directly to the airport, as long as the passport in question had expired within the past 10 years, according to the State Department.