Turkish officials said Friday that two Syrian generals, a colonel and two sergeants have defected from the Syrian army and crossed into Turkey, a day after Syria's deputy oil minister also deserted President Bashar Assad's regime.

The defections come amid reports of Syrian army assaults on the northern Syrian province of Idlib, which borders Turkey, and as U.N. humanitarian chief Valerie Amos toured Syrian refugee camps along the Turkish-Syrian border before talks with Turkish Foreign Minister Ahmet Davutoglu.

The officers' defections are significant because most army defectors so far have been low-level conscripts.

Assad's regime has suffered a steady stream of low-level army defectors, who have joined a group of dissidents known as the Free Syrian Army, now numbering in the thousands.

On Thursday, Syria's deputy oil minister became the highest-ranking civilian official to join the opposition and urged his countrymen to "abandon this sinking ship" as the nation spirals toward civil war. Abdo Husameddine, 58, announced in a video that he has defected.

The officers and the two sergeants were in a group of some 234 Syrians who have fled to Turkey since Thursday, Yusuf Guler, the administrator for the Turkish border town of Reyhanli told Turkey's state-run Anadolu Agency, without providing any information on their identities.

Guler said the defectors and other refugees were taken to camps near the border with Syria. Some 12,000 Syrians now live in six refugee camps in the region.

Brig. Gen. Mostafa Ahmad al-Sheik, who fled to Turkey in January, was the highest ranking officer to bolt. In late August, Adnan Bakkour, the attorney general of the central city of Hama, appeared in a video announcing he had defected.

Authorities reported he had been kidnapped and said he was being kept against his will by gunmen. He has not been heard from since.

The U.N. estimates 7,500 people have been killed since the uprising against Assad's regime began last year. Activists put the death toll at more than 8,000.

The uprising began with largely peaceful protests, but faced with a vicious regime crackdown, it has become increasingly militarized.

Turkey, which shares a long border with Syria, has been calling for an end to a crackdown by Syria's government troops, and is set to host a diplomatic conference on Syria's future later this month.

Turkish officials are setting up some temporary housing units near the border to shelter the Syrian refugees, and move them away from tents.