It takes a degree of skill and stealth to make an improvised explosive device and then plant it on a road without getting caught. Tossing a grenade just takes murderous nerve.

In Baquba, a provincial capital northeast of Baghdad, the men of nerve have made their debut.

"There were no RKG attacks here prior to the (Jan. 31 provincial) elections," said a U.S. military intelligence officer who requested anonymity. "The introduction of the RKGs and the attacks are all post-election."

An RKG is a Russian-made anti-tank grenade.

"We've had nine in the city, but fortunately no one has been killed," the military intelligence officer said. "No one has been killed yet, but we've had some wounds from shrapnel, that sort of thing."

RKG is the Russian acronym for Ruchnaya Kumulyativnaya Granata, a handheld shaped charge grenade. It weighs just a bit more than 2 pounds and looks like a World War II German "potato masher," with a stem/handle for throwing and the detonator and explosive charge attached to one end.

The stem, however, is dual-purpose. When the arming pin is pulled and the grenade is thrown, a small drogue parachute is released from the stem to stabilize the grenade in flight.

"They are best suited for populated areas," the officer said. "You have to be in proximity of throwing distance, and you have to be able to get away with it by quickly hiding in a building or hiding yourself in a crowd. It's certainly not suited for a rural environment when you're the only one out there."

The grenade is an anti-armor weapon with an effective range of 20 to 30 meters -- from about 60 feet to 100 feet. Depending on whether the explosive cone container is steel-lined or copper-lined, it can penetrate between 125mm and 165mm of steel plate, respectively.

According to the authoritative British defense analysts Jane's, the RKG-3, originally manufactured in the Soviet Eastern bloc, was used extensively by Arabs in the 1973 Yom Kippur War -- known to Arabs as the War of Ramadan -- with Israel. Longtime Iraqi President Saddam Hussein's arsenal had stocks of the weapon, but those used here appear to be of more recent manufacture, U.S. sources said. Some RKG caches found contained weapons made as recently as 2006. Sources wouldn't disclose their country of origin or by what route they reached Iraq but noted that both Syria and Iran border Iraq.

Diyala province is northeast of Baghdad and shares a border with Iran, which the United States has accused in the past of supplying weapons to Iraq's extremists. U.S. commanders also believe some extremist cells use Iranian territory as a safe haven.

In post-surge Iraq, Diyala remains restive. In the far north there are ethnic tensions between Arabs and Kurds; in the south there are sectarian tensions between Sunni Arabs, the majority of the province's people, and Shiite Arabs. Pockets of extremists -- from al-Qaida to Shiite militias to Sunni nationalists -- still exist and cause mayhem.

In Baquba and its surrounding areas, there is still concern about IEDs planted along roads, about car bombs and suicide vest bombers, although the number of incidents per month is in single digits. Now the RKG has been added to the mix.

"I don't know why" the RKG attacks have started, said Capt. Steve Anderson, commander of Bravo Company, 1st Battalion, 5th Infantry Regiment. "The area had been quiet. We partner with the (Iraqi Security Forces); we do a lot of community work. ...

"If you figure it out, you tell me."

Anderson is working hard with his staff and 1st Brigade, 25th Infantry Division staff to figure out who and why and how to end the attacks. His company, which operates in the Tahrir neighborhood of Baquba, has taken the brunt of the hits. A few weeks ago, five of his soldiers were wounded in an RKG attack while traveling down a street with Iraqi soldiers in an armored Stryker vehicle.