Washington increased security for some flights from the Middle East

Washington has asked some airports in the Middle East to tighten security measures for flights to the US "as a precaution", after the crash of a Russian plane in Egypt, US Homeland Security Secretary Jeh Johnson said today.

As the accident investigation progresses, we will continually evaluate these measures and decide whether additional changes should be made, Johnson added in a statement.

"We have identified a certain number of temporary stricter measures, precautionary measures regarding the security of flights to the US from some airports in the region," he said.

It is about the increased control of items brought into planes, the assessment of airports together with international partners, as well as other "visible or invisible" measures, he added.

These measures are added to the measures already introduced last summer for some foreign airports, which were also adopted by some European countries, US allies.

A source close to the investigation into the crash of the Russian A321 in Sinai, Egypt, estimated today that the analysis of the black boxes, together with other indications, "strongly supports" the assumption that it was an attack.

The Airbus A321 of the Russian company Metrojet with 224 passengers and crew members crashed on October 31 on the way from the Egyptian resort of Sharm el-Sheikh to St. Petersburg 23 minutes after takeoff. No one survived.

US and British officials said they feared a bomb had exploded during the flight, while Russian officials said they would investigate all possible causes of the plane's crash.