The chances of an asteroid slamming into Earth in just seven years from now have been upgraded by NASA.

       The worrying prediction says that the 2024 YR4 asteroid now has a 2.3% chance of hitting us, almost double its previous 1.2% chance.

       The lump of space rock first set off warning systems after it was spotted through advanced telescopes in Chile in December.

       Since then, the asteroid has been put to the very top of the risk list. If it does strike Earth, it will impact on December 22 at 2.02pm and could cause "localised destruction".

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       NASA says it’s likely to land somewhere across the eastern Pacific Ocean, northern south America, the Atlantic Ocean, Africa, the Arabian Sea or South Asia.

       2024 YR4 is thought to be about 40m to 90m wide (about 300ft).

       NASA Asteroid Watch tweeted: “While still an extremely low possibility, asteroid 2024 YR4's impact probability with Earth has increased from about 1% to a 2.3% chance on December 22, 2032. As we observe the asteroid more, the impact probability will become better known.”

       The Planetary Defence blog for NASA added: “As more observations of the asteroid’s orbit are obtained, its impact probability will become better known.

       “It is possible that asteroid 2024 YR4 will be ruled out as an impact hazard, as has happened with many other objects that have previously appeared on NASA’s asteroid risk list, maintained by NASA’s Center for Near-Earth Object Studies. It is also possible its impact probability will continue to rise.”

       The asteroid is currently at level three on the Torino Impact Hazard Scale, a system used to determine how big a threat an asteroid poses to Earth. Level three suggests it has a chance of localised destruction.

       The scale goes all the way to 10, which is complete global catastrophe.

       If this asteroid does hit Earth, it would make impact at about 17,000mph. If it did end up being 90m wide, it would be a “city killer”.

       Space journalist Kate Arkless Gry told Sky News Breakfast: "If it was on the 90m end of the scale, we're looking at what they would call a city killer, where if it was to land on a major city - and there are a few in the potential hit zone - that would be disastrous."