The EU called it "deeply disappointing" and "surprising" that Israel stopped and on Tuesday deported a Spanish MEP who had arrived for an official trip to the Palestinian territories.
European Parliament lawmaker Ana Miranda tweeted that the action by Israeli authorities against her was a "diplomatic affront" and showed "disrespect" to the EU legislature.
Spanish Foreign Minister Jose Manuel Albares also expressed indignation and said "we are demanding an explanation from Israeli authorities".
And EU foreign affairs spokeswoman, Nabila Massrali, told journalists that Miranda's deportation was "surprising" given that "her entry had been authorised expressly by the Israeli authorities".
"We regret the decision" and view it as "deeply disappointing," Massrali said.
She stressed that "respect for all elected MEPs and the European Parliament is essential for good EU-Israel relations".
Miranda had arrived late Monday at Israel's Ben Gurion airport, which also serves the Palestinian territories, with other members of the European Parliament's Delegation for Relations with Palestine.
"Israel did not permit me entry" and put her on the first flight to Madrid early Tuesday, Miranda said.
Last year, the EU and Israel restarted meetings of a joint council after a decade-long pause caused by Israeli anger at Brussels' criticism of expanding West Bank settlements, which are illegal under international law.
But the return of Benjamin Netanyahu as prime minister at the helm of the country's most right-wing government ever has dimmed hopes of improving ties with Europe.
