Foreigners need 'special' permission to visit White House

President Trump introduced the new measure earlier this week.

US President Donald Trump has introduced new measures for foreign nationals interested in visiting the White House.
If you are planning to visit the United States and visiting the iconic White House, you need to contact your respective embassy first.
According to reports, visitors from outside the US must now apply for places for a White House tour. In order to do so, they must contact the embassy of their respective country. The embassy will then process the request for the tour.
British citizens, however, might have a difficult time as UK citizens cannot approach their embassy to apply for a White House tour. According to the British Embassy in Washington, the US Department of State has put tour applications on hold without citing any reason. 
The British Embassy in Washington has suggested potential British tourists to consider tours of the US Capitol Building instead. Tours of the Pentagon are also up for grabs but non-US nationals must submit the British Embassy's mailing address instead of their home address.
Below are the instructions stipulated on whitehouse.gov for potential tourists.

If you wish to visit the White House and are a citizen of a foreign country, please contact your embassy in Washington, DC for assistance in submitting a tour request.

Forms of Identification
All guests 18 years of age or older will be required to present a valid, government-issued photo identification (detailed below). All foreign nationals must present their passport. All other forms of foreign identification will not be accepted.

All information submitted (e.g. name, date of birth, city, etc.) must exactly match the government-issued photo ID you will present when arriving at the White House.

The following forms of photo ID are acceptable for presentation to USSS upon entry to the White House complex:

Valid government-issued United States identification card (e.g. drivers license, military ID, etc.)
Valid United States or other official government-issued passports
No other forms of identification will be accepted; photocopies, expired IDs, or other transmissions of these documents are NOT valid.