Israel has blocked a prominent British pro-Palestinian activist from entering the country, a week after the Knesset passed a bill allowing border officials to turn away foreign nationals who support boycotting Israel.
Hugh Lanning, head of the UK-based Palestine Solidarity Campaign, was denied entry into Israel late on Sunday over his "ongoing actions to promote boycotts against Israel", the immigration authority said.
Lanning was also accused of maintaining ties to leaders of Hamas, the hardline Palestinian group that runs the Gaza Strip.
He flew back to London on Monday morning, authority spokeswoman Sabin Hadad said.
Gilad Erdan, the minister of strategic affairs, told reporters on Monday: "Whoever acts against Israel should understand that the rules of the game have changed.
"No sane country would allow entry to key boycott activists working to harm the country's core interests and lead to its isolation."
The boycott movement, known as BDS, advocates boycotts, divestment and sanctions against Israel in what supporters say is a nonviolent way to promote the Palestinian struggle for independence.
The group, which includes thousands of volunteers around the world, has urged businesses, artists and universities to sever ties with Israel.
Israel sees the boycott movement as a strategic threat and accuses it of anti-Semitism - a claim activists deny, saying they only want to see the occupation end.
Last week, the Israeli parliament adopted a law barring entry to foreigners who support boycotting Israel, a move denounced by human rights groups and the opposition as "thought control" harmful to the country's international standing.
Ben Jamal, the director of the Palestine Solidarity Campaign, called Lanning the "first victim" of the new law.
READ MORE: What is BDS?
"A democratic country does not behave in the way Israel is behaving," he said.
"If Israel believes that by introducing these draconian, undemocratic laws it will intimidate its critics into silence it is mistaken."
A number of measures targeting the BDS movement have been introduced in Israel, the US and Western Europe in recent years.
Last year, Barack Obama approved legislation that required official non-cooperation with groups that boycott Israel, although the bill does not apply to Jewish-only settlements in the occupied West Bank. Around 20 US states have passed anti-BDS bills or are in the process of doing so.
Source: Al Jazeera and news agencies