"Our condolences to the American people for the loss of their ambassador and three members of the embassy staff in Libya." These words were sent in a letter by Khairat El-Shater, deputy guide of Egypt's Muslim Brotherhood, to the New York Times on Friday following the killing of US Ambassador to Libya Christopher Stevens in response to an anti-Islam short film.

Stevens, along with three other embassy staff members, was killed Tuesday night following an attack on the US consulate in Benghazi. Another five Americans and ten members of the Libyan security forces were injured as mobs, allegedly protesting the film, stormed the US mission armed with rocket-propelled grenades.

El-Shater pointed out that he did not hold the American government or its citizens responsible for the acts of "the few" that abuse the right to free expression, despite his displeasure over the continued appearances of such anti-Muslim productions.

El-Shater also condemned the "breach of the US embassy premises" by Egyptian protesters, which he described as illegal under international law.

"Egypt is going through a state of revolutionary fluidity, and public anger must be dealt with responsibly and with caution," the Brotherhood's number-two added. 

On Thursday, the Muslim Brotherhood's official English-language Twitter account (@Ikwanweb) reposted a message from El-Shater, in which he expressed his "relief that none of the US embassy Cairo staff was hurt" and voicing hope that US-Egypt relations would weather the latest developments.

The reconciliatory tweet, however, was posted as the Brotherhood's Arabic-language Twitter account and its official website were both praising the ongoing protests outside the US embassy and calling for a million-man rally on Friday.

One Arabic-language article on the Brotherhood's site sported the headline 'Egyptians rise to defend the Prophet.' Perceiving a contradiction, the embassy tweeted a tart response from its own account: "Thanks. By the way, have you checked out your own Arabic feeds? I hope you know we read those too."

The Brotherhood replied some 20 minutes later, saying, "We understand you're under a lot of stress, but it would be more helpful if you pointed out your exact concern about the Arabic feed."

The brief exchange provided a snapshot into the strains that US-Egypt relations came under this week. It took Egyptian President Mohamed Morsi more than two days to officially condemn the breaching of US embassy grounds by angry protesters.

US President Barack Obama on Wednesday described Egypt as "neither an ally nor an enemy" of the US. "I don't think that we would consider them an ally, but we don't consider them an enemy," Obama said in an interview with Telemundo, excerpts of which were aired by MSNBC.

"And if they [Egypt] take actions that indicate they're not taking those responsibilities, as all other countries do where we have embassies, I think that's going to be a real big problem," the US president added.