US intelligence officials have warned that allies Russia and China pose a significant threat to Taiwan as they ramp up their military cooperation.

       Lieutenant General Jeffrey Kruse, director of the Defense Intelligence Agency, told a congressional hearing on Thursday of the emerging threat of a conflict between China and Taiwan, adding that Russia's ties with China would bring a "second front".

       He said: "Bottom line is that basically if we were to have a conflict with one, the chances are we would have a second front."

       Kruse was asked whether the Pentagon's knowledge of the counties' relationship is being taken into consideration in defence planning.

       He responded: "From the Department of Defense perspective, that would certainly be the case, and it just has to be taken into account whether or not we actually believe there would be two full-up fronts. That is analysis and assessments that will mature over time."

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       Director of National Intelligence Avril Haines was also quizzed during the hearing on whether China and Russia would assist each other in a potential conflict with the US and its allies.

       She said: "We see China and Russia, for the first time, exercising together in relation to Taiwan and recognising that this is a place where China definitely wants Russia to be working with them, and we see no reason why they wouldn't."

       The two nations currently have a "no limits" partnership which began shortly before the war in Ukraine and helped to boost Russia's economy after stringent sanctions from the West left it increasingly isolated.

       In return, Russia has provided China with cheap oil and natural gas. They have also conducted five joint military drills since 2022.

       Though China denies providing Russia with weapons for its war in Ukraine, Ukrainian researchers have said that Chinese companies are providing Moscow with drones and drone components.

       Despite the Chinese Communist Party has never ruled over Taiwan, it still claims it as its territory, and President Xi Jinping has publicly stated he is not against using force to claim it as his own.

       The US is an important ally of Taiwan, remaining its largest weapons supplier even after it switched official relations from Taipei to Beijing in 1979.