A welder showers sparks across the seven-meter-high fence of galvanized steel mesh and coils of barbed wire in Israel's southern desert, bordering Egypt.
Israel began building the fence two years ago but workers now are rushing to complete it this year. The fence has taken on greater importance for Israel since Egypt's popular uprising ousted long-time President Hosni Mubarak a year ago.
The Egyptian government withdrew many of its security forces from the Sinai peninsula to deal with civil unrest and lawlessness in its cities. As a result, Israeli commanders say the Sinai has become a security threat.
"This is a 'hot' border now and terror is on this border like any other border we have in Israel," said Israeli Army Lieutenant Colonel Yoav Tilan, speaking to reporters on a recent tour of the border area.
"And we are copying and modifying our techniques like in different other borders to this border, solely on the motive that this is now a terror-threatened border," he explained.
Growing border threat
Israeli commanders say they face some kind of security threat every day along this border, stretching from the Red Sea to Gaza.
The desert area has long been a route for smugglers, mostly marginalized Bedouins, who make a living trafficking in cigarettes and illegal drugs. During the 1990s, the border became a conduit for human trafficking, mostly women destined for the sex trade.
In recent years, increasing numbers of illegal immigrants, mostly from Africa, have tried to cross to Israel, fleeing political oppression or seeking jobs.
And since the fall of Libya's Moammar Gadhafi, Egyptian forces say they have intercepted Libyan weapons in the Sinai.
Tilan says the smuggling routes have now become part of the infrastructure for terrorism.
"These are terrorist organizations that move freely along the Sinai Peninsula, many cells, different organizations, with one motivation: to infiltrate this border and attack civilian and also military targets along this border," he said.
Deadly attack
Last August, gunmen crossed from Egypt and attacked Israeli civilians on a road near the border.
Eight Israelis were killed and 30 were wounded. Israeli forces pursued and killed three of the attackers; three Egyptian soldiers were killed in cross-fire. The rest of the attackers fled back into Egypt.
Tilan said although the dead gunmen have not been identified, some of the ammunition they carried were traced to groups in Gaza.
He believes many of the terrorist organizations in the Sinai have links to extremists in Gaza, which is controlled by the Palestinian movement Hamas.
A senior Israeli commander, who could be quoted only on condition of anonymity, said Africa has become a center of gravity for terrorism as far as Israel is concerned.
As a result, the Israeli military has sent additional troops to the Egyptian border area and it is reinforcing the fence with electronic surveillance.
Countermeasures
But some old-fashion methods still prevail. A dirt road about ten meters wide runs beside the fence on the Israeli side. It is covered with soft dirt. Its purpose is to show the tracks left by infiltrators.
Israeli Army Lt. Col. Salah el-Khayeb commands the tracking unit in the Israeli forces here. Its members are mostly from local Bedouin tribes.
El-Khayeb says every morning there is a patrol along the border and in every patrol there is a tracker who looks for signs or objects and determines whether there was an infiltration.
The smugglers use a variety of techniques to hide their tracks. These include walking on foam rubber strips or metal stands and using tree branches, cloth or even motorized leaf-blowers to erase evidence of their passage.
But El-Khayeb says a good tracker can still see spot remnants of such tracks.
Israeli commanders say infiltrations have declined significantly in areas where the fence is in place. But the barrier is only a third complete.
Israeli officers also say infiltrators are adapting, becoming more cunning, more rapid and more violent -- and using high-tech equipment like night-vision binoculars.
As a result, the Israelis are working closely with Egyptian security forces who, they say, have the same interest in halting the increasingly menacing traffic.