London: A pro-Islamic State (IS) Twitter account has threatened to attack Los Angeles International, John F Kennedy International and Heathrow airport as the US prepares to celebrate July 4 Independence Day weekend, the media reported on Saturday. The attacks will be carried out on planes "flying from Heathrow to the US" and warned that "there will be a device placed in either [sic] Heathrow, LAX or JFK airports," Telegraph reported, citing the Twitter account. The terror attack warning was revealed by the Site Intelligence Group, an organisation that tracks the online activity of terrorist groups. "We all need to be vigilant to the global threat of terrorism -- in Britain we keep all aspects of aviation security under constant review and work closely with our international partners to mitigate risks," Transport Minister Lord Ahmad of Wimbledon was quoted as saying. Security has already been beefed up across the US airports. The threat comes in the wake of a deadly attack on Istanbul's Ataturk airport where three Islamic State suicide bombers killed 41 persons injured over 239 others. At least five persons were killed and 18 rescued as Bangladeshi forces on Saturday started an operation to free up to 40 hostages held by about eight to nine gunmen -- claimed to be affiliated to the IS militant group -- who attacked a restaurant in the diplomatic quarter of Dhaka late on Friday.