Frontex chief ambivalent on pulling out of Greece

"It's an advice from the fundamental officer and of course we take that into account," Leijtens told MEPs in the parliament's civil liberties committee.

But Leijtens said that pulling the agency out of Greece could lead to "serious consequences, also in our ability and capability to save lives."

In public, Grimheden has made the same argument in the past. And Leijtens, during his candidacy grilling by MEPs to lead the agency, claimed he wouldn't hesitate to withdraw operations if needed.

The alternating positions poses questions on the ambivalence of an agency to trigger article 46, which gives Leijtens the power to suspend operations in a country where fundamental rights violations are likely to persist.

But his hesitation also follows numerous egregious allegations of rights abuse by Greek authorities, including video footage of the Greek coast guard allegedly setting people on a raft adrift, including a six-month old baby. And the agency's rights office registered 23 serious incidents reports on Greece last year, more than any other EU state.

It also comes in the wake of the 14 June sinking of the Adriana trawler that has likely drowned over 500 people, a tragedy that continues to demand accountability, amid conflicting accounts of what happened.

The agency had on 13 June spotted the Adriana with a surveillance aircraft from its Italian operation. Running low on fuel, it then returned to base, after having alerted the Greek and Italian authorities about the sighting.

"Then we offered two times to early deploy one of our drones," said Leijtens, noting that the Greeks never responded. He said the closest Frontex operated boat, covering Greek territory, was a full two-day sail from the Adriana.

"So all we could have delivered is situational awareness," he said.

Meanwhile, doubts are being cast on whether the Greek authorities will carry out a proper investigation into the sinking.

Official accounts by the Greek coast guard conflict with the testimonies by those who survived, as do a series of media investigations.

Ylva Johansson, EU migration commissioner, also speaking alongside Leijtens, said such an investigation is needed "not least for the Greek reputation."

The Greek general prosector is only mandated to probe the suspected smugglers behind the shipwreck, while the Greek naval court is investigating the actions of the Greek coast guard, she said.

"We need to trust on the judicial system in member states," said Johansson.

Others are demanding for an international investigation.

"A tragedy repeated is a crime, and this crime, I'm sorry to say, bears political signatures. The EU institutions cannot stand idly by," said Greek Syrzia MEP Kostas Arvanitis.

Similar comments were made by the EU's Fundamental Rights Agency, also on Thursday.

In a report, it said the EU should find ways to apply the transparency and accountability principles laid out in EU rules when investigating migrant shipwrecks.

"The drownings of so many migrants — on average eight every day last year — is a cause of deep shame for Europe," said FRA's director, Michael O'Flaherty, in a statement.