The recent arrest of an organized cell in the northern West Bank inspired by al-Qaida’s ideology is a stark reminder of the expanding nature of the threat facing Israel. Today, threats come not only from the enemies it has long known, such as Hamas and Islamic Jihad which target Israel at home, but from new and potentially more dangerous ones, such as radicalized individuals in the West Bank or formalized groups such as Jaish al Islam and Jund Ansar Allah in the Gaza Strip, that are ideologically aligned with al-Qaida and are eager to globalize the assault on Israel.

In the West Bank, where intelligence and law enforcement agencies can keep close tabs on terrorist recruitment in general, and Salafi-Jihadi elements in particular, al-Qaida-inspired terrorism has appeared only sporadically through individuals radicalized from the Internet or traveling abroad. The ability of West Bank Arabs to travel and study abroad creates opportunities for radicalization and recruitment, but the area’s relatively strong and growing civil society makes it less amenable to the development of organized Salafi-Jihadi groups. While even small cells or lone wolves could potentially carry out significant terrorist attacks, the threat is minimized by the strong Israeli and growing Palestinian security presence in the West Bank.

THE GAZA Strip, however, is another story. In fact, even as Gazan terrorists floated barrel bombs toward Israel last week, a virtual terrorist salvo was also being directed out of Gaza.

The al-Fallujah web forum featured a Salafi-Jihadi blogger from Gaza who called on al-Qaida in the Arabian Peninsula to attack Yemeni Jews (and even a Hamas official in Yemen) in an effort to broaden the terrorist threat from Gaza well beyond the shores of southern Israel.

For Gazan jihadists, like this blogger, Israel, Jews and even Hamas are all enemies. By engaging in secular politics, failing to institute Shari’a, and cracking down on fellow Palestinians who do attack Israel or threaten its rule, Hamas has created a vacuum Salafi-Jihadi groups have been keen to fill. Such groups are in large part comprised of disillusioned Hamas members and a small number of foreign fighters – from places as diverse as Yemen, Egypt, Syria, France and Belgium. Some foreign fighters from Europe have reportedly “come with their credit cards” and financed jihadist activities while in Gaza. And yet none of the Salafi-Jihadi groups in the Gaza Strip are formally tied to al-Qaida.

Contrary to the conventional wisdom perpetuated by media reports that regularly inflate their numbers and capabilities, membership in Gaza’s various Salafi-Jihadi groups totals just 200-300 combined.

While small in number, such groups nonetheless “think big” and are regularly plotting large-scale attacks, such as infiltrating Israel with booby-trapped trucks. Their capabilities have been significantly enhanced by the entry of several dozen foreign fighters starting in 2005, after Israel’s withdrawal from Gaza

In 2009, reports emerged that some individuals who traveled to Iraq to fight US forces have since turned to Gaza. Israeli defense officials express concern that this influx will increase as US forces are rotated out of the country. While few, if any, of these foreign fighters are directly affiliated with al-Qaida, they bring operational know-how and a globally driven ideology. The fear is that such a “glocal” ideology could serve as a bridge between traditional Palestinian nationalism and al-Qaida’s global Salafi-Jihadi ideology. The former theoretically allows for a two-state solution; the latter requires adherents to actively wage violent jihad against all infidels and apostates until an Islamic state can be declared on as large a territory as possible.

TO BE sure, while Salafi-Jihadi groups in Gaza have failed to execute spectacular attacks, they are eager to catapult themselves to center stage and demand the attention of al-Qaida’s core leadership, something they could do with a single successful attack.

In the words of a Gaza jihadist, “So far al-Qaida has not sponsored our work. We are waiting to carry out a big jihadist operation dedicated to Sheikh Osama Bin Laden. Our course and doctrine are similar to those of al-Qaeda. If al-Qaeda asks us to pledge allegiance to it, we are completely ready for it.”

Frustrating such ambitions demands a concerted and multi-layered effort by Israel and its allies. Securing the Egypt-Gaza border to prevent the infiltration of still more foreign fighters is a first critical step, but border security cannot be predicated on securing the last line of defense.

As Israel has demonstrated, targeting weapons smuggling convoys on land and ships at sea, only with enhanced intelligence-sharing and cooperation can human, weapons or other smuggling operations be detected “upstream” before reaching its borders.

Salafi-Jihadi groups are not mollified by progress toward peace. To the contrary, they are motivated to undermine peace with Israel – temporary or permanent – at all costs. A second step is therefore maintaining an active counterterrorism posture in the West Bank and exacting a high cost for continued attacks stemming from Hamas-controlled Gaza, regardless of who carries out any given attack. Only under continued pressure will Hamas, the de facto governing entity, challenge these groups’ efforts to target Israel, fellow Palestinians and Western interests.

The good news is that al-Qaida as such has not yet come to the West Bank or Gaza. The West Bank features still small numbers of al-Qaida inspired individuals and the few Salafi-Jihadi groups in Gaza lack significant numbers and are in the rare position of facing challenges from Israel and Hamas both.

The bad news is that a pernicious ideology inspired by al-Qaida has taken root among some Palestinians. While the number acting on this ideology remains small, they operate within a society at some level sympathetic to their ideas. According to a new Pew Research Center poll, 51 percent of Palestinians express confidence in al-Qaida leader Osama Bin Laden.

Barrel bombs and mortars, while dangerous, pose no strategic threat to Israel. But if al-Qaida’s global jihad were to truly set roots in the West Bank or Gaza it would markedly increase the nature of the terrorist threat it faces.

A robust security presence keeps the West Bank under control. Planning strategically now could prevent Gaza from ultimately becoming the next Somalia or Yemen. And with a number of Yemeni and other foreign fighters already there, time is of the essence.

The writer directs the Stein program on counterterrorism and intelligence at The Washington Institute for Near East Policy. A former US counterterrorism official, he is the co-author of Deterred but Determined: Salafi-Jihadi Groups in the Palestinian Arena (January 2010).