(CNN) -- Iran's Baha'i community -- a religious minority that has faced persecution in the Islamic republic -- is reporting a string of arson attacks targeting homes and vehicles.
A house "went up in flames" in Kerman on July 18 only weeks after the residents' car had been torched, said Bani Dugal, principal representative of the Baha'i International Community to the United Nations. Those incidents followed a series of threatening phone calls, Dugal said.
"As would be expected in the light of the mistreatment Baha'is in Iran are routinely receiving, the officials who investigated the fire either ignored or dismissed obvious signs of suspicious activity, including a muffled explosion, simply saying that it was the result of an electrical problem," she said.
The group also listed several incidents since February, and Dugal said there had been at least a dozen cases of arson targeting the Baha'is in the last 15 months.
Mohammad Mohammadi, press attache for the Iranian delegation at the United Nations in New York, said the Baha'is are just repeating claims they have made before.
"They are full of claims, not verified by anybody," he said.
The attacks, reported on Monday by the Baha'i movement, come on the heels of the arrests of seven members of Iran's national Baha'i coordinating group in March and May. The Baha'is say the seven have been jailed in Evin Prison in Tehran without charge.
"These latest attacks follow the authorities' attempts to deprive the Iranian Baha'i community of its leadership," Dugal said.
"As Baha'is worldwide watch with alarm this escalation in violence ... their fears that a sinister plan of persecution is unfolding become increasingly confirmed. Their only hope is that enough voices of protests are raised around the world to compel the government in Iran to put an end to this violence."
Sarah Leah Whitson, the Human Rights Watch Middle East director, said "there's been an uptick" in the repression of the Bahai community in Iran.
"Such arson attacks would be a natural outcome of the government's most recent campaign to vilify and attack the Baha'i community, disparaging them and their beliefs in the press with a spate of anti-Baha'i articles in the government-run press and arresting several of the community's leaders on still-unspecified charges," Human Rights Watch's Whitson said.
"When the top religious authorities insist on characterizing Baha'is as apostates and encourage a climate of hate against the Baha'i community, one would well expect these sorts of violent outbursts to be directed against them."
The government has said that the seven people recently detained were held for "security issues" and that the Baha'is are members of a group working "against national interest," a claim denounced by the Baha'is.
The Baha'is say the latest arrests are part of a pattern of religious persecution that began in 1979. That's when the monarchy of the Shah of Iran was toppled and an Islamic republic was created.
The Baha'is say members of its community have been killed, jailed and "otherwise oppressed" because of their religion.
Dugal has said the government's philosophies were based largely on the idea that there could be "no prophet following Mohammed" and that the faith "poses a theological challenge to this belief."
The Baha'is regard their founder Baha'u'llah as the most recent in the line of Messengers of God that stretches back beyond recorded time and that includes Abraham, Moses, Buddha, Krishna, Zoroaster, Christ and Mohammed.
The Baha'is-- regarded as the largest non-Muslim religious minority in Iran -- say they have 5 million members across the globe, and about 300,000 in Iran.