Attacks by organized groups against migrants, refugees and activists have been increasing in Greece, the Athens-based Racist Violence Recording Network (RVRN) said yesterday, and it called for zero tolerance towards racist violence.

In its 2017 annual report, the RVRN said the living conditions of refugees and migrants on Greek islands, where thousands are stranded in dire, overcrowded camps, drove xenophobic rhetoric in local communities, sometimes with "extreme manifestations."

It found violent assaults had increased in Athens too, and said perpetrators appeared to execute instructions given to them by their organizations based on pre-meditated plans.

"The RVRN alarmingly observes an increase in the number of assaults committed by groups employing 'hit-and-run' like practices," the report said.

On the island of Leros, asylum-seekers reported they had been attacked by groups of motorcyclists using sharp objects. One pregnant woman said she was targeted because of her headscarf. In Athens, one man was verbally abused and beaten in the face at a bus stop, the report said.

The RVRN, established in 2011 by the U.N. refugee agency in Greece and the National Commission for Human Rights, gives a broad definition of racist violence as "criminal or violent acts or behavior against people because of their ethnic origin, color, religion, gender identity, sexual preferences or disabilities."

On the basis of interviews with victims, it recorded 102 incidents of such violence in 2017, more than a third of which resulted in injury. That was up from 95 incidents in 2016.

Hostility towards migrants and refugees has risen in Greece since it plunged into an economic crisis in 2010. Actual numbers are likely to be higher than those reported as victims are sometimes too scared to report attacks to the police.

Asylum seekers in Greece suffer widespread sexual violence and harassment in the country's sub-standard, overcrowded reception centers, the U.N. said in early January.

In 2017, the U.N. refugee agency (UNHCR) received reports from 622 survivors of sexual and gender-based violence on the Greek islands, around one-third of whom said they had been assaulted after arriving in Greece. But UNHCR spokesman Cecile Pouilly said that there is a reluctance to report such violence out of fear, shame and concerns about discrimination, retaliation and stigma.

"The actual number of incidents is therefore likely to be much higher than reported," she told reporters in Geneva, acknowledging that the U.N. has only a "very partial picture of what the reality is," according to Agence France-Presse (AFP).

Pouilly said the situation was most worrying in the reception and identification centers of Moira on Lesbos and Vathy on Samos, "where thousands of refugees continue to stay in unsuitable shelter with inadequate security." These centers are currently holding around 5,500 people -- double their capacity, she added.

"In these two centers, bathrooms and latrines are no-go zones after dark for women and children," she said, adding, "Even bathing during the daytime can be dangerous.

In Moira, one woman told UNHCR staff that she had not showered for two months for fear of being attacked.

The country of 11 million people recorded 58,661 applications last year, making Greece the European country with the highest number of asylum seekers per capita, according to the Greek Asylum Service.