Tehran, Iran (CNN) -- An Iranian extremist group claimed responsibility Friday for a pair of suicide bombings Thursday that killed at least 27 people and wounded dozens more in the southeastern Iranian city of Zahedan.
The announcement was made on the official website of Jundallah, also known as the People's Resistance Movement of Iran.
"This operation is in response to the continuous crimes committed by the Iranian regime in Balochistan," the statement said. "These two men sacrificed their souls to humiliate the regime and have proved that our misery will only end with Jihad and by scandalizing the criminals."
The claim came as a high-ranking official of Iran's Islamic Revolutionary Guards Corps implicated "the U.S., Israel and some European countries" in the attack, the semiofficial Fars News Agency reported.
Yadollah Javani, the head of the Revolutionary Guards Corps' political bureau, said terrorist groups under the auspices of the United States, Israel and some Western countries were involved, according to Fars.
The blasts occurred in front of Zahedan's Grand Mosque, and the second explosion followed within minutes, Iran's state news agency IRNA reported.
Health Minister Marzieh Vahid Dastjerdi said the death toll from the bombings reached 27 on Friday, according to IRNA. He said 270 were injured and 11 were in critical condition.
"It is not yet possible to announce the exact number of those killed and injured in the incident," a police official said, according to IRNA. Zahedan is the capital of Sistan-Baluchestan province, which borders Pakistan.
A lawmaker in Zahedan told IRNA that "the two explosions were the result of suicide bombings. First, someone in a woman's clothing tried to enter the Jam-e Mosque in Zahedan but was prevented from entering."
It was not immediately known whether that person was a man or a woman, said Hosseili Shariari, a Zahedan member of parliament.
Three or four people died in the first explosion, and while people were trying to help those victims, the second suicide bomber detonated his explosives, he told IRNA.
In London, England, Foreign Office Minister Alistair Burt said Britain "strongly condemns" the attack and said he was "horrified" by it.
"In targeting a busy mosque, the bombers claimed the lives of peaceful worshippers and passers-by," he said.
In Washington on Thursday, U.S. Secretary of State Hillary Clinton condemned the attacks.
"The United States extends its sympathy to the families and loved ones of those injured and killed," she said in a statement. "We also call for the perpetrators of this horrific attack to be held accountable for their actions."
The Friday prayer leader of Tehran blamed the United States for the bombings.
"The crime that was committed in Zahedan showed the dirty hands of the United States that came through the sleeves of mercenaries," Hojjatoleslam Sedighi said. The cleric's first name was not reported.
Hezbollah, the Lebanese militant group backed by Iran, condemned the attack, saying it was "part of the arrogant campaign against the Islamic Republic of Iran, by some organizations and terrorist groups that have been raised by the hands of Western intelligence."
"Hezbollah is sure that Iran -- with its iron fist -- will overcome these criminal aggressions, as it should bring the murderous terrorist organizations to an end on one hand, and sever any American-Western attempt to use these criminals to achieve their arrogant objectives inside the Islamic Republic on the other," the group said Friday.
In October, in the same province, a suicide bomber blew himself up as participants headed to a conference between Shiite and Sunni Muslim groups in the city of Sarbaz.
At least 29 were killed in that bombing, including five senior officers of the Revolutionary Guard Corps.
Jundallah also claimed responsibility for that attack.
In the past, the predominantly Shiite central government in Tehran has accused Jundallah of fomenting unrest in the province. Iran has alleged that the United States and Saudi Arabia are funding the group. Jundallah says it is fighting for the rights of Sunni Muslims in the country.
CNN's Shirzad Bozorgmehr contributed to this report.