There is growing concern among security officials in Israel that cells associated with al-Qaida could carry out terrorist attacks against Israel from Syria.

In recent weeks, growing involvement of al-Qaida operatives in the fighting against the Syrian army has been noted. Extremist Islamists identified with various factions of the global jihad movement, including al-Qaida, currently number several thousand across Syria, and they are taking part in the fighting all over the country. Some are fully cooperating with the rebels' Free Syrian Army, but some officers from the opposition forces contend that the Islamist activists will endanger Syria's future following the fall of Syrian President Bashar Assad.

One of the scenarios being studied by security officials in Israel is that these activists will attempt action against Israel in the near future so as to goad Assad into a confrontation with Israel. However, there is greater concern that global jihad activists will take advantage of the security vacuum in Syria after Assad's fall to turn Syria into a global jihad bastion and increase attacks on Israel.

This scenario seems very possible in light of the increasing participation of al-Qaida activists in the fighting in Syria and the simultaneous chaos and weakening of the regime.

Websites identified with organizations like al-Qaida have recently been releasing the names of activists from all Arab countries that have been killed in the fighting in Syria. Among them are al-Qaida supporters from Iraq, Yemen, Jordan and Saudi Arabia. The main group identified with al-Qaida is one that goes by the name Jabhat al-Nusra li-Ahl al-Sham (meaning "the front for the protection of the Syrian people" ). It has released increasing numbers of videos on the YouTube website, as well as announcements of responsibility for military actions against the forces of the Syrian regime. This is a different pattern of activity than that of the rebels' Free Syrian Army, although the al-Qaida-identified group frequently cooperates with the rebels.

The threat to Israel from the north comes at a time when, in the south, the Sinai has become a refuge for al-Qaida operatives from across the Middle East. Members of the local population assist them, and Hamas and Islamic Jihad also partially cooperate with them.

On Friday, Hamas released a leader of the extremist Salafi sect, Hesham al-Sa'eedni, who was responsible for the murder of Italian peace activist Vittorio Arrigoni, about 18 months ago. Sa'eedni was apparently released following pressure from Salafists in Egypt and Jordan. Sa'eedni led a group called Al-Tawhid wal-Jihad, identified with the global jihad movement. The group abducted Arrigoni after Sa'eedni was arrested, in an attempt to secure the latter's release, and then executed the Italian out of fear that Hamas was about to ferret the group out.

Meanwhile, more than 250 people were killed in the fighting in Syria over the weekend. A good many of the victims were killed in fighting in Damascus, Deir Ezzor and Aleppo.

The opposition and the regime are also fighting a war on the propaganda front, with each side claiming extraordinary victories. Representatives of the Syrian army are adamant they have managed to take over Damascus and have cleared out pockets of rebel resistance. One of the regime's senior officers was quoted as saying the situation in Damascus was "good." The opposition, for its part, is claiming to have taken over more than 60 percent of Aleppo, Syria's second-largest city.

The Syrian army is continuing its aerial and artillery bombardment of areas of Aleppo where the rebels are active, but the rebels managed briefly to take control of the Syrian broadcasting building in Aleppo, suspending television and radio broadcasts. Although the rebels then withdrew, their forces claim they are surrounding the area. The Syrian army is apparently trying to regain control in Damascus and then turn its full forces on Aleppo.

The commander of the rebels' military council in Aleppo, Abdul-Jabbar Mohammed Akidi, said over the weekend that Assad's regime was being helped by Tehran and that thousands of Iranian fighters had come to Syria over the past few days. The rebels have been claiming for some time that Iranian and Hezbollah forces are prolonging the regime's survival, although Iran has vehemently denied these reports. On Saturday, Iranian television reported that 48 Iranian pilgrims had been abducted from a bus outside Damascus near the Shi'ite Sayeda Zeinab Mosque. Iranian officials blamed "terrorists" for the act.