SANAA, Yemen (CNN) -- Non-essential U.S. Embassy officials are being urged to leave Yemen after it was revealed that an American woman was among those killed in Wednesday's attack.
The attack killed six Yemeni police and four civilians after suspected al Qaeda-linked insurgents disguised as Yemeni forces bombed the outer wall of the embassy in Sanaa. They then opened fire on Yemeni authorities.
The death of the American woman was confirmed on Thursday by deputy U.S. State Department spokesman Robert Wood.
"We are saddened to confirm that among the victims of yesterday's terrorist attack against our Embassy in Sanaa, Yemen, was Susan El-Baneh, an American citizen."
El-Baneh, 18, of Lackawanna, New York, had just been married and was visiting family in the Yemeni capital. Her husband, a Yemeni national, also died in the attack, Wood said.
Six attackers -- including one wearing a suicide vest -- were also killed, according to Mohammed al-Basha, spokesman at the Yemeni Embassy in Washington.
Yemeni forces have reportedly rounded up at least 25 suspects connected to the attack.
Diplomatic sources told CNN Thursday they are aware of the reports. They noted that usually after such incidents, Yemeni security forces cast a broad net "bringing in the usual suspects, and then nothing comes out of it."
The State Department issued a similar directive in April after attacks against the embassy and a residential compound. That order was lifted last month, but has again been re-instated.
In a travel warning issued Thursday, the State Department said it would not authorize any travel outside the capital city of Sanaa, and asked U.S. citizens to defer all non-essential travel into the country.
Those choosing to remain in Yemen were asked to "exercise caution" -- be vigilant, avoid crowds, keep a low profile, and vary times and routes for travel. Watch more about the attack »
"The Department remains concerned about possible attacks by extremist individuals or groups against U.S citizens, facilities, businesses, and perceived threats," it said.
The embassy temporarily closed after the Wednesday morning attack so staff could help Yemeni investigators. It plans to resume normal operations on Saturday, after the normal weekend in Yemen.
The attackers detonated two car bombs in an attempt "to breach the wall ... and then have the attackers go on foot through this breach in the wall," State Department spokesman Sean McCormack said.
"The attack bears all the hallmarks of an al Qaeda attack," he added.
Yemen also believes al Qaeda was responsible for the attack, al-Basha said.
Media reports said Islamic Jihad in Yemen -- which is affiliated with al Qaeda -- has claimed responsibility for the attack.
The U.S. State Department had previously warned of violence that it attributes to Islamic extremists in Yemen.
In March, three mortar rounds landed near the embassy, wounding Yemeni students at a nearby school and Yemeni government security personnel, the State Department said.
The next month, an expatriate residential compound in the Hadda neighborhood was attacked by mortar fire. Suspected extremists fired two mortar rounds toward the Yemen Customs Authority and Italian Embassy in April, as well, but no one was hurt.
CNN's Diane Ruggiero in Washington and Schams Elwazer and Ben Wedeman in Sanaa contributed to this report.