Iran has stepped up its protest over the knighthood awarded by Britain to Salman Rushdie, whose 1988 novel The Satanic Verses outraged many Muslims.
Sir Salman has said he is thrilled by the honour
Iran's foreign ministry summoned the UK ambassador in Tehran and said the knighthood was a "provocative act".
Pakistan voiced similar protests, telling the UK envoy in Islamabad the honour showed the British government's "utter lack of sensitivity".
Britain denied that the award was intended to insult Islam.
Iran summoned UK ambassador Geoffrey Adams to protest against the knighthood.
"This insulting, suspicious and improper act by the British government is an obvious example of fighting against Islam," Iran's Foreign Ministry Director for Europe, Ebrahim Rahimpour, was quoted as saying by the state-run Irna news agency.
"It has seriously wounded the beliefs of 1.5 billion Muslims and followers of other religions."
Mr Rahimpour added that Iran held the British government and Queen Elizabeth II "responsible for the circumstance of this provocation".
In Islamabad, British High Commissioner Robert Brinkley was called to Pakistan's foreign ministry several hours earlier.
The envoy was told that the honour countered attempts by both countries to build mutual understanding.
For his part, Mr Brinkley expressed "deep concern" over reported comments by Pakistani Religious Affairs Minister Mohammad Ejaz ul-Haq, suggesting that the award could justify suicide attacks.
"If someone commits suicide bombing to protect the honour of the Prophet Muhammad, his act is justified," the minister said, according to Reuters news agency.
The minister later clarified his statement, saying extremists could use it to justify attacks.
Pakistan's parliament passed a resolution on Monday condemning the award.
The BBC's Barbara Plett in Islamabad says the diplomatic row is heated but that so far it has stayed mostly within official circles.
Both Iran and Pakistan are Islamic republics with an overwhelmingly Muslim population which saw violent protests against The Satanic Verses in 1989.
A fatwa against Sir Salman was issued the same year by Iran's spiritual late leader Ayatollah Khomeini, calling for his execution.
The move forced Sir Salman to go into hiding.
Sir Salman, 60, was one of almost 950 people to appear on the Queen's Birthday Honours list, which is aimed at recognising outstanding achievement.
The Indian-born author's book was published in 1988.
It describes a cosmic battle between good and evil and combines fantasy, philosophy and farce.
It was immediately condemned by the Islamic world because of its perceived blasphemous depiction of the Prophet Muhammad.
In 1998, the Iranian government said it would no longer support the fatwa, but some groups have said it is irrevocable.
The following year, Sir Salman returned to public life.