Firefighters put out a fire at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria’s President Bashar Al-Assad in the old city of Aleppo

WASHINGTON — In desperate efforts to gain ground on battlefields, frustrated governments in the Mideast and Africa are using barrel bombs against their enemies, launching the cheap, quickly manufactured weapons as a crude counter to roadside blasts and suicide explosions that insurgents have deployed with deadly success for years.

New evidence that they are being used in Iraq after being dropped on civilian populations in Syria and Sudan has raised concerns that governments in a number of unstable nations will embrace them.

Described as “flying IEDs” — improvised explosive devices — barrel bombs have the power to wipe out a row of buildings in a single blast and can kill large numbers of people, including unintended victims.

“It’s fair to say that a lot of governments are losing control of the counterinsurgency,” said Michael Knights, an analyst at the Washington Institute for Near East Policy. “They’re also watching what they see in Syria, and they feel like their air power is what is making the difference.”

“Barrel bomb” is a catchall term for a large container packed with fuel, chemicals or explosives and often scraps of metal, most often dropped from helicopters or planes. However, they also have been found on Israeli beaches, where authorities believe they washed up after being released by militants on the Gaza Strip.

Barrel bombs are attractive to governments that have aircraft but limited munitions or money to launch enough conventional weapons, like missiles, to rival their enemies.

Sudan’s army began dropping barrel bombs into rebel areas starting in late 2011, according to human rights watchdogs, as the nation’s south split off and created a new country. In December 2012, Susan Rice, then US ambassador to the United Nations, said she was “gravely concerned” about the reported attacks.

In Syria, forces controlled by President Bashar Al-Assad began a continuing barrel bomb campaign in 2012 against areas controlled by rebels and insurgents, killing thousands in his effort to prevail in the three-year civil war that has left more than 160,000 people dead. As recently as Wednesday, the State Department reported evidence of barrel bomb strikes on three neighborhoods in the divided northern city of Aleppo.

Last month, new evidence that Iraq’s army dropped between four and 10 barrel bombs on insurgent strongholds in the country’s Sunni-dominated Anbar province, which borders Syria, spurred US officials to warn Baghdad to immediately desist or risk American support and aid. Four government officials in Washington and Baghdad said the attacks stopped within days of the US demand. The government officials, all of whom are familiar with the mid-May conversations with Iraqi Prime Minister Nouri Al-Maliki, spoke on condition of anonymity because they were not authorized to discuss the talks.

But several Iraqis interviewed this week in Falluja told The Associated Press the bombings have continued. They said the attacks usually come at night, so they aren’t caught on video. Militants in Falluja have boasted they have discovered about 20 barrel bombs that did not explode on impact and are using them to make their own weapons.

British munitions expert Eliot Higgins, who analyzes weapons used in Syria’s war, described remains of exploded barrel bombs in Anbar that appeared to be similarly manufactured — meaning they were likely built by the government instead of random troops or insurgents.

Officials familiar with the incidents say the Iraqi army may have dropped large containers of explosives onto areas inhabited by the Al-Qaeda splinter group known as the Islamic State in Iraq and the Levant, or ISIL. The distinction is important, they say, because it means the attacks did not target civilians, as Assad’s forces have done in Syria.

“What’s happening now in Iraq definitely started in Syria,” Human Rights Watch researcher Erin Evers said. “If I were Al-Maliki, and seeing Assad next door using the same tactics without a slap on the wrist and gaining ground as a result, it stands to reason he would say, ‘Why the hell not?'”