Berlin, March 23 : Several European countries have updated their travel advisories for the US this week following the detention of multiple European nationals, including German citizens, upon arrival.

Germany's Foreign Office said on Saturday that it is taking the recent incidents involving German travellers seriously, Xinhua news agency reported.

"We have clarified and now clearly emphasise that an Electronic System for Travel Authorisation (ESTA) approval or a US visa does not, in every case, authorise entry into the US," a spokesperson told public broadcaster ARD's Tagesschau.

The advisory update follows reports of three German nationals being detained at US entry points, including one green card holder. Two of the individuals have since returned to Germany.

In response to the incidents, Britain also revised its travel advice, warning of strict enforcement of US immigration laws.

"You may be liable to arrest or detention if you break the rules," the Foreign, Commonwealth and Development Office said on Thursday.

Britain's foreign office confirmed earlier this month that it was providing support to a British national reportedly detained at the border in the US, according to Reuters.

Finland issued a similar update on Friday, cautioning that even valid travel documents might not guarantee entry under current US policies.

The Finnish Foreign Ministry also noted recent changes requiring visa or ESTA applicants to declare both their gender and gender at birth, which could result in denied entry if inconsistencies are found.

Both Denmark and Finland have updated their travel guidance regarding people's gender markers on their travel documents.

Additionally, Finnish authorities warned travellers to avoid large gatherings in major US cities, citing the risk of politically motivated demonstrations turning violent.

According to Finnish broadcaster Yle, the tightened advisories reflect evolving US immigration policy under President Donald Trump's new term.

On Friday, Canada also updated its travel guidelines for entering the US.

Canadians and foreign nationals who visit the US longer than 30 days "must be registered with the United States government," the government's website warns ' and that failure to comply could lead to "penalties, fines, and misdemeanor prosecution".

/IANS