China inaugurated a missile plan in Iran last month, even as the United States and its allies were pressing Beijing to support a new round of tough economic sanctions on the Islamic Republic over its nuclear program, Jane's Defense Weekly reports.

It's a military relationship that goes back two decades and, in light of Russia's reluctance to provide the Iranians with advanced air-defense missile system to counter possible U.S. or Israeli airstrikes, is set to expand.

Robert Hewson, editor of Jane's Air-Launched Weapons, reported that the factory for assembling and producing Iran's Nasr-1 -- Victory 1 -- anti-ship missile was opened March 7.

The Nasr is identical to China's C-704 anti-ship missile, Hewson says. Iran's burgeoning defense industry, much of it controlled by the Islamic Revolutionary Guards Corps, has been producing Chinese-designed anti-ship missiles such as the C-801 since the early 1990s.

The C-704, developed by China Aerospace Group, targets ships of 1,000-4,000 tons displacement and is the equivalent of the U.S. AGM-119 anti-ship missile. With a range of 106 miles and a 240-pound warhead, the C-704 has a kill probability of 95.7 percent.

The Iranians, possibly with Chinese assistance, have even developed improved versions such as the Noor, an upgraded version of China's C-802, with a longer range than the original and over-the-horizon capabilities.

Indeed, Hewson observed that "Iran has gone further than China in fielding the C-802, taking what was previously a land- and ship-launched weapon and producing an air-launched version that can be carried by Mi-17 helicopters and fast-jet types."

Over the years Iran has developed a range of anti-ship missile systems from the Chinese weapons that gives the Islamic Republic's regular navy and the IRGC's naval arm the capability to exert a considerable degree of control over waters in the Gulf and the Arabian Sea.

This is the area from which U.S. naval forces would strike if hostilities erupt.

On Saturday, the IRGC concluded its annual three-day Great Prophet exercises in the Strait of Hormuz, the choke point gateway to the Gulf and a key energy artery, in a show of defiance against the United States.

The Nasr is a medium-range weapon that can be launched from warships or shore batteries and its development and planned mass production has been trumpeted by Tehran at a time when Iran's military forces are making preparations to counter possible attacks.

"In a methodical and deceptively modest manner China has helped Iran take charge of all its surrounding waters and this work between the two nations continues," Hewson reported.

"Follow-on versions of the Nasr are being developed to include an air-launched variant.

"There are other cooperative tactical missile programs under way and China's design bureaus have displayed several 'export only' weapons (such as the C-705 lightweight cruise missile) that would seem set to follow the established route into Iran," Hewson added.

"With such a solid relationship established between the two countries it is not difficult to see why China has been reluctant to commit to the Western push for sanctions against Iran."

China, ever hungry for energy sources to fuel its expanding economy, imports around 12 percent of its oil from Iran and seeks to secure Iranian natural gas through overland pipelines -- another reason it has shown little enthusiasm for new U.N. sanctions on Iran.

Hewson said no Chinese envoys were seen at the opening of the Nasr factory conducted by Iran's hard-line defense minister, Brig. Gen. Ahmad Vahidi, but the event marked "another milestone in the continuing military/industrial bond between the two countries."

Hewson observed that unlike Russia, China "has been very successful in offering Iran technology and capabilities that are actually wanted, as opposed to those that might be 'nice to have.'

"A path has been found through the factions within Iranian officialdom (and its armed forces) to deliver products that build trust in Beijing. In return, China gains influence with Tehran that can be parlayed into access to Iran's natural resources."

While these Chinese-origin systems have provided Iran with invaluable missile technology, this has had little or no impact on the development of its ballistic missile capabilities.

"Iran's strategic weapons can only (ultimately) involve it in a losing battle with the United States,' Hewson concluded, "but its tactical weapons have already altered the regional balance of power in a much more practical way."