China has a “fleet” of surveillance balloons of different shapes and sizes, which it has deployed over five continents, US officials have claimed. The allegations on Wednesday came as salvage work continued off the South Carolina coast for the debris from a high-altitude Chinese balloon a US jet fighter downed on Saturday after it had crossed the whole of the continental US. “We’re not alone in this,” said the US secretary of state, Antony Blinken. “We’ve already shared information with dozens of countries around the world both from Washington and through our embassies. We’re doing so because the United States was not the only target of this broader programme which has violated the sovereignty of countries across five continents.” The Pentagon spokesperson, brigadier general Patrick Ryder, said the FBI and the Naval Criminal Investigative Service were working to catalogue the wreckage of the downed balloon and transfer it to the mainland for further examination. The Pentagon has published photographs of sailors on small navy boats gathering parts of the balloon from the surface, but most of the equipment payload – said to be the size of a regional passenger jet – has sunk to the sea bed. President Joe Biden said Wednesday that the US was “not looking for conflict” with China despite tensions over the balloon. “We’re going to compete fully with China, but ... we’re not looking for conflict – and that’s been the case so far,” he said in an interview with the PBS network. Asked if the incident had caused major damage to the relationship with Beijing, Biden said: “No.” The Pentagon assesses that Chinese surveillance balloons flew over parts of the US three times during the Trump administration and once previously under Biden’s tenure, and escaped immediate detection. One Chinese spy balloon “drifted past Hawaii and across Florida” as it “circumnavigated the globe” in 2019, according to a US air force intelligence account reported by CNN. Ryder said the US had found a way of spotting the approaching balloons and the most recent one was tracked from the time it approached in the Aleutian islands in the north Pacific. “When you look at the scope of this programme – and the fact that we know that these balloons have been spotted operating over at least five continents and regions like Latin America, South America, south-east Asia, east Asia and Europe – it demonstrates why, for the department of defence, China remains the pacing challenge,” Ryder said. “It calls into question why China feels that it’s OK to violate the sovereign airspace of nations in a way that is inappropriate and unacceptable.” At a meeting with Blinken, the Nato secretary general, Jens Stoltenberg, was asked if he was aware of overflights of other members of the alliance, but did not answer directly. “What we see is that China, over the last years, has invested heavily in new military capabilities, including different types of surveillance and intelligence platforms,” Stoltenberg told reporters. “We also see increased Chinese intelligence activities in Europe, again on different platforms. They use satellites, they use cyber, and – as we’ve seen in the United States – also balloons. So we just have to be vigilant. We need to be aware of the constant risk of Chinese intelligence and then step up what we do to protect ourselves.”