A convoy of U.S. Humvees streamed through the midnight darkness, following the border as soldiers scanned the endless flats with night-vision goggles. The thin earthen berm separating northern Iraq from Syria lay just a few hundred yards to their right, but what was out there was almost a total mystery.
"We've lost them," Lt. Stuart Burnham, 24, of Springfield, Va., said with faint resignation, ordering the convoy to turn around and head back to the small U.S. base at this border crossing town. "Maybe next time."
Less than an hour earlier, air surveillance of the area had picked up signs of as many as 20 people trying to sneak into Iraq near an Iraqi Border Patrol fort. Now they had faded away.
Soldiers and Iraqi border officials don't know exactly what crossed into Iraq on Monday night, whether it was the usual parade of smugglers ferrying sheep, cigarettes and fuel, or perhaps foreign fighters hauling in bundles of cash. The 45 miles of border monitored out of Combat Outpost Heider and a series of Iraqi forts here are porous, especially at night, and U.S. authorities say it is simply impossible to know who and what are passing through.
U.S. and Iraqi officials have been trying for years to crack down on foreign fighters and funds moving across the border from Syria. But training efforts for Iraqi Border Patrol officers have picked up steam only over the past year. Better equipment such as new pickup trucks arrived only months ago.
Local forces still lacking resources
U.S. trainers say the Iraqis are getting much better at their jobs but still lack vital resources, have far too few men to adequately monitor this stretch of desert and farmland, and are up against a furtive smuggling culture that has been in place for centuries.
"At night, it's impossible to cover all this terrain," said Army Maj. Bill Tomlin, 37, of Kennedy, Ala., who is a border transition team leader in Rabiyah. "We're not seeing mass movements through here of bad guys, weapons and explosives, but it's very hard to catch individual people."
Much of the smuggling traffic is strictly commercial. Sheep are moved from Iraq to Syria, where herders can garner nearly $100 more per head on the black market. Refined gasoline goes in the other direction, to Iraq, where prices are exponentially higher.
U.S. officials have seized stocks of baseball caps, women's underwear and cigarettes traversing the border in an attempt to avoid heavy tariffs at official border crossings.
But sometimes the smugglers are leading small groups of foreign fighters and young men recruited as suicide bombers, U.S. commanders in Iraq's northern region say.
Lt. Col. Fred Johnson, deputy commander of the 3rd Stryker Brigade Combat Team, 2nd Infantry Division in Mosul, said that it's not so much the foreign fighters that draw concern but the sacks filled with cash that allow fighters to buy weapons and explosives that are already in Iraq.
U.S. and Iraqi forces recently found a group of 10 donkeys crossing the border packed with an enormous amount of cigarettes, raising concerns about the amount of money that could also go across the border.
"If 10 donkeys can carry 66,000 packs of cigarettes, how much money can they carry?" said Capt. Paul Curry, 32, of Huntsville, Ala. Curry commands Apache Troop, 3rd Squadron, 4th Cavalry Regiment at a U.S. camp just a few feet from the official Rabiyah point of entry into Iraq. Border controls have improved, he said, but "we have no idea what we have missed so far. It's like looking for a needle in a haystack."
Iraqi officials who control the gateway say that as many as 2,000 people with Iraqi passports and as many as 500 foreigners pass into Iraq through Rabiyah each day, in addition to nearly 300 commercial trucks, 80 cars and as many as 30 buses.
Raid Jamal, assistant manager of the border crossing, said that the border generates 3 billion Iraqi dinars each month -- about $2 million -- in customs duties and taxes but that the system has been mired in corruption for many years and needs to be cleaned up.
U.S. troops in the area are concerned that controls are too loose. For instance, the passport office is sparse and includes a single officer sitting at a desk behind a barred window where travelers line up to show their passports. The officer simply enters the information from each passport into a small ledger.
"The only thing he's really doing is nothing more than creating a historical log," said 1st Sgt. Richard DeLeon, 40, of Shafter, Calif., also a member of Apache Troop. "We can't scan your passport to find out if it's fake, we can't scan your photo. You can come in if you have a legitimate passport or a good fake. The weapons are already in Iraq. All you really need to do is bring money."
Lt. Col. Malcolm Frost, who commands 3rd Squadron, 4th Cavalry Regiment, said the Rabiyah border entry needs shoring up. He cited plans to add high-tech passport technology, which would make it easier to identify foreign fighters, and a new, secure processing office in the next couple of months.
One of the few anti-smuggling measures the crossing already has is X-ray technology that scans trucks. It can detect trucks with false bottoms and compartments in which people and weapons can be hidden. On Monday, Frost watched as a truck was scanned and turned back for carrying used car parts, which are illegal to transport into Iraq and could be used to hide bomb parts.
"We're continually improving the ability to detect," Frost said. But the miles of earthen berm away from the crossing have proven difficult to monitor.
Tomlin, who trains border patrol officers, said that there are roughly 400 officers on his stretch of border and that they are getting steadily better at their jobs. They have new Chevrolet pickup trucks for patrolling and serviceable weapons. But he said they lack the infrastructure to support the equipment, and gasoline, food and electricity are hard for them to get.
He said he believes the units are about five months away from being able to operate as a competent border patrol. It could be years, however, before they can sustain themselves.