In other times, Mirwais Samadi would have welcomed a campaign to deter his compatriots from opting to become illegal migrants and embarking on the often dangerous trek from Afghanistan to Europe.

By far the worst part of his job as Afghanistan’s ambassador to Athens – apart from the strange limbo he has found himself in representing a nation whose leaders he refuses to recognise – is notifying families back home of loved ones who died along the way. Invariably they are the victims of smuggling networks motivated solely by profit.

But Greece’s announcement of a media blitz to discourage “illegal migrant flows” from Afghanistan only weeks after Taliban militants seized power has also left the ambassador appalled.

In the face of European hostility to Afghans heading west – and as the new regime vows to rule according to a ruthless interpretation of Islamic law – Samadi, like other career diplomats still loyal to the old regime, has found himself imploring EU governments to think again.

“This is a time for solidarity, not the time for the west to turn its back on the people of Afghanistan and abandon them or have a campaign that urges [them] to stay,” he told the Guardian in his cavernous ambassadorial office. “In normal circumstances I would not be in favour of illegal movement but when people are forced to leave due to the security situation and for fear of their lives, what should we do?”

The centre-right government of the prime minister, Kyriakos Mitsotakis, unveiled the EU-funded initiative, saying its goal was “to make clear that Greece guards its borders in an organised way and does not allow illegal migration flows”.

Amid fears of the country again becoming the gateway for thousands of Europe-bound Afghans desperate to escape the excesses of Islamist hardliners still seeking international legitimacy, the Greek migration ministry admitted the move had been prompted by “the latest geopolitical developments in Afghanistan”.

Under the campaign, mainstream Afghan newspapers and social media will be targeted in what officials have called a blitzkrieg of messaging aimed at dissuading Afghans from paying smugglers to help them flee.

Platforms including YouTube will be employed, with videos reportedly being prepared to convey the unvarnished reality of what awaits people if they succeed in reaching Greece through irregular means. This week asylum seekers on Samos were moved into a “closed” and highly fortified reception centre – the first of five EU-funded facilities on Aegean isles – that is encircled by military-style fencing and equipped with magnetic gates more resonant of a prison than a migrant camp, NGOs say.

In his smart blue suit, cufflink shirt, loafers and yellow tie, Samadi, who served in Washington prior to arriving in Athens in 2019, is visually everything the Taliban are not. Like Afghan ambassadors worldwide, he was appointed by the now exiled foreign minister, Mohammad Hanif Atmar, with whom he and his counterparts still confer as representatives of Kabul’s “legitimate government” in weekly online Zoom meetings.

“No one has told us to take down our flag,” he said, pointing to the ensign the Islamic Republic used before the Taliban takeover. “We are in a limbo situation where no one recognises the Taliban, but how long that will go on for, no one knows.”

Western powers have not recognised the Taliban’s recently announced government, and its foreign minister, Amir Khan Muttaqi, has yet to nominate any representatives to replace Afghanistan’s contingent of ambassadors abroad if diplomatic relations are established. As a result, its overseas missions remain in the hands of pro-western career diplomats astounded by the course of events in their homeland, unsure of how they will survive financially and holding meetings with officials who have fled the country.

Samadi, whose wife is a prominent women’s rights activist, belongs firmly in that school. His time in Athens has been a wake-up call to the desperation that drives Afghans to seek refuge in Europe, often at great personal cost.

Eight months ago, the diplomat says, he too pressed the case for his compatriots not to embark on perilous journeys to Greece, long on the frontline of migrant and refugee arrivals from Asia, Africa and the Middle East.

“The hardest part of my job is having to inform families of children who are found dead in the sea, or in the forests around the Greek-Turkish [land] border,” he said. “In interviews with all the major TV channels in Afghanistan I encouraged people, back then, not to attempt to come illegally. I said please don’t send your children on these dangerous journeys. But now circumstances are completely different.”

Describing the situation as unique, he warned: “If countries close their borders it will be a human catastrophe … now is not the proper time for such a campaign, we have all seen the heartbreaking scenes.”

Instead, he said, all nations should be holding the Taliban to account because if the situation inside Afghanistan were to improve – with better job opportunities, security and freedom of expression for women, human rights activists and civil society – the desire to leave would diminish.

“Now is the time to make the Taliban accountable,” he said. “If the Taliban don’t enter negotiations with other Afghan political groups and agree to form a broad-based, inclusive government based on rule of law and respect for the rights of everyone then we should not be stopping but helping to get vulnerable people out.”

Afghans account for the largest number of asylum seekers in Greece – although the vast majority are headed on elsewhere – with an estimated 40,000 registered in the country.

A nondescript building perched on an elevation in Athens’ northern suburbs, the Afghan embassy was deluged daily by hundreds requiring passports and other documents to apply for refugee recognition status, prior to the pandemic.

“So far only about 10,000 of the 40,000 here have had their requests processed,” Samadi said. “The rest are still waiting. Over 95% arrive without documents and over 90% are in a very bad economic situation. They have sold everything, their clothes, properties, jewellery to make the journey.”

Before the Greek campaign even gets off the ground there are questions as to whether it will have any effect. “Migrants trust their own sources and have their own way of understanding things,” said Gianluca Rocco, the chief of mission of the International Organization for Migration (IOM), the UN migration agency, in Greece. “They don’t listen so much to campaigns. Usually they trust their network of families and friends more than messages from governments of Europe.”

Since the fall of Kabul, Greece – which also took part in US-led evacuation efforts in August – has taken in about 65 Afghans refugees, including six female MPs who arrived en route to being resettled with their families in the US. Athens’ foreign ministry described them as “defenders of fundamental values, freedom of expression and gender equality”.

Samadi said he could sympathise with the domestic pressure the Greek government faced but that it was also up to the EU to stand up for the core values it represented.

“Thousands [of refugees] have arrived here and I know Greece has challenges, but there should be a joint EU effort to address this common challenge,” the ambassador said. “People in Afghanistan now are in a state of shock. But if the situation doesn’t improve then definitely in the coming months, once winter has passed, there is a strong possibility of big migrant flows towards Greece and the EU.”