President George W. Bush has decided to give Russia notice that the United States will withdraw from the 1972 nuclear treaty that bans testing of missile defence systems, US government officials said today.

US President George Bush and Russian President Vladimir Putin failed to resolve their dispute over US missile shield plans yesterday but pledged on a harmonious final day of summitry to fight terrorism and deepen US-Russian ties.

President Vladimir Putin said today he was willing to cut Russia’s nuclear arsenal to under 1,500 warheads as long as the process was ’’controlled’’ and the 1972 ABM treaty was preserved.

World governments responded nervously to President George W Bush’s decision to build a shield against ballistic missile attack, dubbed Son of Star Wars, with some saying they feared the plan could jeopardise global security.