The Syrian Observatory for Human Rights said Ahrar al-Sham, Jund al-Aqsa and Nusra Front groups took control of the city after four days of intense fighting. By taking Idlib, capital of the Syrian province with the same name, insurgents now control a second province after the Islamic State stronghold Raqqa.
The capture of Idlib, with more than 100,000 residents, would be a blow to President Bashar al-Assad because the city is a strategically important link between Damascus to Aleppo.
Some 13 people were killed near polling stations in five attacks that may have been carried out by Boko Haram militants or other political malcontents. The tense race between incumbent President Goodluck Jonathan and former military ruler Mohammadu Buhari has polarized voters on religious, ethnic and sectional lines.
Jonathan, a Christian from the conservative People's Democratic Party enjoys support in the south, while challenger Mohammadu Buhari, a Muslim from the All Progressives Congress, is popular in the north.
In a promise to keep this election the fairest in Nigerian history, handheld biometric thumbprint readers were used as voter identification for the country's 69 million voters. But the devices, riddled with technical glitches, only caused frustration among voters, including Jonathan, who was forced to leave and come back to vote after the problems were solved.
Polls were supposed to open by 8 a.m., but by 12:30 p.m. only 81 percent were accepting voters. The Independent National Electoral Commission also reported staff members and voting materials were hijacked. Adding to the problems, the commission website was hacked by a group calling itself the Nigerian Cyber Army.
"Sorry xD Your Site has been STAMPED by TeM Nigerian Cyber Army FEEL SOME SHAME ADMIN!! Security is just an illusion," a statement on the website read.
Nigerian Watch quoted a source saying U.S. Marines arrived at a nearby airport in Ghana in anticipation of evacuating Americans from Nigeria in the event of post-election violence.
The election was originally scheduled for Feb. 14, but was delayed due to the threat of Boko Haram. Since then, the Nigerian military said it has made great advances on the extremist group, but Boko Haram continue its attacks on the area.