WASHINGTON - Passengers traveling on certain US-bound foreign airline flights will have to check electronic devices larger than a cell phone once US authorities formalize a new ban in response to an unspecified terrorism threat, US officials told Reuters on Monday.The new rule is expected to be announced Tuesday by the Department of Homeland Security, the officials said, adding that it had been under consideration since the US government learned of a threat several weeks ago.A source said the rule would cover around eight to 10 foreign airlines. A separate government official confirmed an Associated Press report that the ban will affect 10 airports in eight countries in the Middle East and North Africa.Reuters reported earlier the ban would include airlines based in Jordan and Saudi Arabia. The officials did not name the other countries.No American carriers were affected by the ban, the officials said. Passengers would be allowed to carry in their checked luggage larger devices like tablets, portable DVD players, laptops and cameras.CNN, citing an unnamed US official, said the ban on electronics on certain airlines is related to al-Qaida in the Arabian Peninsula and that some information came from a recent US special forces raid in Yemen. Reuters could not immediately confirm the CNN report, but Reuters has reported the group has planned several foiled bombing attempts on Western-bound airlines.Royal Jordanian Airlines said in a tweet on Monday that US-bound passengers would be barred from carrying most electronic devices aboard aircraft starting Tuesday at the request of US officials, including those that transit through Canada. Passengers can still carry cell phones and approved medical devices.Al Riyadh newspaper, which is close to the Saudi government, reported that the civil aviation authority had informed "airlines flying from the kingdom's (Saudi) airports to US airports of the latest measures from US security agencies in which passengers must store laptops and tablets" in checked in baggage.Al Riyadh quoted a civil aviation authority source as saying that these measures from senior US authorities were relayed to the Saudi interior ministry.Saudia Airlines confirmed in a tweet that US transportation authorities had barred carrying larger electronic devices in cabin luggage.The White House declined to comment.A spokesman for the US Department of Homeland Security, David Lapan, said the agency has "no comment on potential security precautions, but will provide an update when appropriate. Homeland Security Secretary John Kelly called congressional lawmakers this weekend to notify them of the plan, congressional aides said.In July 2014, the Homeland Security Department stepped up security of US-bound flights, requiring tougher screening of mobile phones and other electronic devices and requiring them to be powered up before passengers could board flights to the United States.