Deputy Secretary of State John Negroponte said Thursday that the United States has concern on the use of Chinese weapons in Iraq and Afghanistan as well as the Asian giant's continued sale of arms to Iran. Giving a briefing to the Congress in Washington, John Negroponte said that the United States has conveyed its concern to China about Chinese weapons or Chinese-designed weapons showing up in some of these battle areas, be it Iraq or Afghanistan.  He told that the US military in Iraq had said its troops had found Chinese-made missiles  which they believe were smuggled in by groups in Iran aiming to arm militants fighting US-led forces. The US military has repeatedly accused Iranian-linked groups of training Iraqi extremists in the use of armor piercing weapons known as explosively-formed penetrators (EFPs).