By Karolina Tagaris

ATHENS (Reuters) - A group of Afghan refugees in Greece protested against their living conditions on Monday by chanting "Liar!" as they tried to block a minister from entering the former Athens airport terminal where they have been stranded for months.

Children stuck inside the compound climbed up a metal gate while dozens of protesters pushed and shoved one another as they shouted "Go, Go!" at Migration Minister Yannis Mouzalas. One man handed him a crying child as he reached the chained gate.

About 1,600 refugees and migrants live at Hellenikon, a former airport complex that also houses abandoned venues used in the 2004 Olympic Games. Of those, 600 live in the old arrivals terminal, sharing tents in unsanitary conditions.

"We have a bad situation in this camp. It's like one year in jail," said an Afghan man who identified himself as Massoud.

Human rights groups, including Amnesty International and Human Rights Watch, have criticized conditions in Greece's makeshift and formal camps, describing them as deplorable and unfit for humans.

"The situation in Greece ... is still very concerning to us," said Monica Costa of Amnesty International, who is on a fact-finding mission at Greek camps this week.

"There are still thousands of people languishing in camps that are not prepared for long-term stay," she said.

Greece has long said it plans to clear out Hellenikon - which housed up to 3,000 refugees and migrants in scorching temperatures last summer - after agreeing to lease it to private investors under its bailout program.

"Hellenikon must be cleared out," Mouzalas reiterated on Monday.

The protesters were demanding better quality food, better sanitation facilities and hot water.

"I completely understand their pain and hardship. We are trying to ease it as much as we can," Mouzalas said.

About 60,000 refugees and migrants have been in Greece for nearly a year after border shutdowns throughout the Balkans halted the onward journey many planned to take to central and western Europe.

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Costa said Amnesty researchers had observed "psychological deterioration, a lot of stress," in the camps, exacerbated by lengthy asylum procedures and uncertainty over the future.

Greek authorities have yet to determine the cause of death of three migrants who died within a week in one camp on the island of Lesbos this month.

"Since the closure of the Balkan route, this humanitarian crisis unfolded, and we have already said that this crisis was completely avoidable," Costa said.

(Editing by Pritha Sarkar)