The United States has unveiled enhanced security measures for flights to the country designed to prevent having to expand an in-cabin ban on laptop computers.

The measures, which European and US officials said would begin taking effect within three weeks, include enhanced passenger screening, heightened screening of electronic devices for explosives and the expanded use of sniffer dogs.

But there are concerns that the increased screening will lead to additional delays for passengers.

SEE WORLD: US tightens security to limit laptop ban