Turkish President Abdullah Gul said Saturday his country's fighter jet shot down by Syrian air defense forces may have violated Syria's air space.

Mr. Gul said it is “routine” for warplanes flying at high speed to cross borders for short distances. He said a probe would determine if the U.S.-made F-4 jet was brought down in Turkish airspace.

The fighter jet was shot down over the Mediterranean Sea Friday.

Syria has acknowledged downing the plane because it trespassed on Syria's territorial waters. Syrian authorities said they shot down the fighter jet in accordance with laws that govern such situations.

Syrian and Turkish forces are working together to search for the two missing Turkish pilots.

Also Saturday, Syrian Prime Minister Riad Farid Hijab named a new cabinet, retaining the same foreign, defense and interior ministers, while violence continued.

The British-based Observatory said at least 40 people have been killed across the country since Friday.

The International Committee of the Red Cross, meanwhile, condemned the killing of a Red Crescent volunteer in Syria a day earlier, in the fourth such incident in the country's continuing unrest.

The ICRC and the Syrian Arab Red Crescent issued a joint statement Saturday, saying the death of 23-year-old Bashar al-Youssef came at a time when the two groups are “virtually the only organizations able to work in areas affected by the violence in Syria.”

The organizations said Youssef was shot while on first-aid duty and was wearing a uniform clearly marked with the Red Crescent emblem. He died of his wounds a few hours later.

Relations between Turkey and Syria are tense, with Turkey condemning Syria's bloody crackdown on protests against the government of President Bashar al-Assad.

Turkey has joined nations such as the United States in saying President Assad should step down because of the uprising in his country.

Turkish Prime Minister Recep Tayyip Erdogan said, following an emergency security meeting Friday, that Turkey will take the “necessary steps” to respond to the shooting down of the fighter jet after the facts are known.