Washington has signed more than $1 billion in new missile contracts in the three months since it announced plans to withdraw from a key Cold War-era arms treaty, campaigners said Thursday.

"The withdrawal from the Intermediate-Range Nuclear Forces (INF) treaty has fired the starting pistol on a new Cold War," warned Beatrice Fihn, who heads the Nobel Peace Prize-winning International Campaign to Abolish Nuclear Weapons (ICAN).

US President Donald Trump announced last October that his country would leave the Intermediate-Range Nuclear Forces (INF) agreement concluded between the US and the former Soviet Union in 1987.

Washington, which accused Russia of violating the treaty through a new missile system, began the official process of withdrawing from the pact in February.

Russian President Vladimir Putin responded by saying Moscow would also leave the INF treaty, which is considered the cornerstone of global arms control.

In the three months following the October announcement, the US government "proceeded to arrange no less than $1 billion in new missile contracts", according to a report by ICAN and another anti-nuclear campaign group, PAX.

The report detailed over $1.1bn in new contracts with six mainly US companies. US defence contractor Raytheon saw the biggest windfall, tallying 44 new contracts worth some $537 million.

Lockheed Martin meanwhile scooped up 36 new contracts, worth $268m, while Boeing grabbed four new contracts totalling $245m, the report found.

'Congress should investigate'

"Congress should investigate the lobbying roles of Boeing, Lockheed Martin and Raytheon who took the lion's share of these contracts," Fihn said in a statement.

The report authors acknowledged that it was unclear if all of the new contracts awarded between October 22, 2018 and January 21, 2019 were for new nuclear weapon production.

"What is clear is that there is a new rush towards building more missiles that benefit a handful of US companies and intend to flood the market with missiles regardless of their range," they said.

At a global level, the report found that governments are currently contracting at least $116bn (102 billion euros) to private companies in France, India, Italy, the Netherlands, Britain and the US for the production, development and stockpiling of nuclear weapons.

At the same time, it stressed that the private sector involvement in the arsenals of China, Israel, North Korea, Pakistan and Russia remain largely hidden, with little insight into how much is being contracted and which companies are getting the deals.

Many of the outstanding contracts identified in the report were granted around 2015 and are set to expire in 2020, but some of the contracts have far longer time frames.

For example, one contract for a key component necessary to launch US Intercontinental Ballistic Missiles runs until at least 2075, the report showed.

"President Trump is heralding the need for global denuclearisation, but US deeds, and those of nuclear-armed allies do not match those words," said Susi Snyder, PAX nuclear disarmament programme manager and the lead author of the report.

"We see the US and other states planning for a nuclear-armed century, with contracts to maintain weapons through at least 2075, despite growing domestic and global calls to reverse course," she lamented.