A British student was deported from Israel and issued with a 10-year ban from entering the country after authorities said he was a "security risk" due to his use of Twitter.
Gary Spedding, from Belfast, travelled to Tel Aviv's Ben Gurion airport on an easyJet flight from Luton on Thursday and was interrogated and searched at immigration, Sky News reports.
The Alliance Party youth wing member and Huffington Post columnist, 23, had travelled to the country to meet Israeli politicians and non-governmental organisations (NGOs).
Speaking to the BBC, he said he was detained overnight and put on a flight back to the UK on Friday.
He said he was deported and issued with the ban because of his campaigning on Twitter.
Tweeting while he was being held, Spedding wrote: "Being detained at Israeli immigration. Lots of threats, they've went right through my phone. I'm about to be transferred to detention centre".
In one tweet he said: "Israeli authorities had my phone for around 5 hours. Prevented me from contacting family, British embassy or colleagues in Israel/Palestine".
He added: "Just been subjected to another horrendous set of searches including very personally invasive 'body search' - felt all near my underwear etc".
A spokesperson for the Israeli Embassy in London said: "Mr Spedding's entry into Israel was denied due to his involvement in organising a violent protest in Queen's University, Belfast, in which an Israeli representative was attacked, and others were forced to take shelter to prevent being hurt.
"No country has an obligation to allow foreigners who have been involved in violent activities targeting its nationals to enter its territory."