MULTAN, PAKISTAN // Whenever a homemade bomb kills a US soldier in Afghanistan, the chances are its main ingredient came from a factory in Pakistan.
The trend has emerged as the latest source of friction in already frayed US-Pakistan relations.
A US congressional panel has frozen US$700 million (Dh2.57 billion) in aid to Pakistan until it gives assurances it is helping fight the spread of bombs by regulating the distribution of calcium ammonium nitrate fertiliser from the Pakarab company.
US officials have visited the complex in Multan over the past two years to seek the management's help in preventing militants from smuggling fertiliser that can be used to make bombs to Afghanistan. Company officials say they have co-operated.
Bags containing ammonium nitrate, used in many improvised explosive devices (IEDs), now have different colouring.
The company is also trying to dye the fertiliser differently to help authorities track it.
"It is wrong to single Pakistan and us out, especially as we are doing all they want us to do," said Pakarab Fertilizer's chief executive officer, Fawad Mukhtar. "This is made throughout the region and Pakistan is not the only source ... huge quantities of this fertiliser are made in Iran, Uzbekistan and Central Asia."
The freeze on US aid was agreed as part of a defence bill that is expected to be passed this week.