Hundreds of people were killed on Wednesday when Egyptian security forces moved in to clear camps in Cairo occupied by supporters of ousted President Mohammed Morsi.
Armed vehicles dispersed protesters who had been holding sit-ins around Nahda Square and the Rabaa al-Adawiya mosque in the capital.
The president was removed by the army on 3 July.
Here are some international reactions to the latest violence.
The secretary general condemns in the strongest terms [Wednesday's] violence in Cairo. Just days ago, the secretary general renewed his call for all sides in Egypt to reconsider their actions in light of new political realities and the imperative to prevent further loss of life.
The secretary general regrets that Egyptian authorities chose instead to use force to respond to the ongoing demonstrations. He conveys his condolences to the families of those killed and his wishes for a full and speedy recovery to those injured.
In the aftermath of [Wednesday's] violence, the secretary general urges all Egyptians to concentrate their efforts on promoting genuinely inclusive reconciliation. While recognising that political clocks do not run backwards, the secretary general also believes firmly that violence and incitement from any side are not the answers to the challenges Egypt faces.
Spokesperson for Secretary General Ban Ki-moon
The United States strongly condemns [Wednesday's} violence and bloodshed across Egypt. It's a serious blow to reconciliation and the Egyptian people's hopes for a transition towards democracy and inclusion.
In the past week, at every occasion, perhaps even more than the past week, we and others have urged the government to respect the rights of free assembly and of free expression, and we have also urged all parties to resolve this impasse peacefully and underscored that demonstrators should avoid violence and incitement.
[Wednesday's] events are deplorable and they run counter to Egyptian aspirations for peace, inclusion, and genuine democracy. Egyptians inside and outside of the government need to take a step back. They need to calm the situation and avoid further loss of life.
We also strongly oppose a return to a state of emergency law and we call on the government to respect basic human rights including freedom of peaceful assembly and due process under the law. And we believe that the state of emergency should end as soon as possible.
Secretary of State John Kerry
We are following the ongoing situation in Egypt with great concern. The confrontation and violence... is not a way forward to address the main political issues and challenges the country is facing at the moment.
We have taken note that the Egyptian security forces are geared towards clearing the protest camps and the reports about deaths and injuries in this respect are extremely worrying.
Let me reiterate that the EU's position is that the violence does not lead to any solutions and that is why we are urging strongly all parties to exercise maximum restraint.
Statement on behalf of foreign policy chief Catherine Ashton
The Kingdom of Saudi Arabia, its people and government, stood, and stand by today, with its brothers in Egypt, against terrorism.
I call on the honest men of Egypt and the Arab and Muslim nations... to stand as one man and with one heart in the face of attempts to destabilise a country that is at the forefront of Arab and Muslim history.
Statement from King Abdullah read out on state television
We watched from world televisions as the coup-makers in Egypt explicitly massacred those who wanted their votes to count in a democracy. We have described this from the beginning as a coup, but the West never said that was a coup, and they tried to soften it, describing it as an intervention.
I believe that Egyptian people who believe in martyrdom will recover their rights sooner or later. If the West does not take serious steps, democracy throughout the world will be questioned by those who resisted the military coup in Egypt, did not resort to violence, did not use weapons despite all provocations.
Prime Minister Recep Tayyip Erdogan
Iran is following the bitter events in Egypt closely, disapproves of the violent actions, condemns the massacre of the population and warns of the serious consequences.
Undoubtedly the current approach to developments in Egypt strengthens the likelihood of civil war in this great Islamic country.
Foreign ministry statement
I am deeply concerned at the escalating violence and unrest in Egypt, and regret the loss of life on all sides. The UK has been closely involved in intensive diplomatic efforts directed at reaching a peaceful resolution to the standoff. I am disappointed that compromise has not been possible.
I condemn the use of force in clearing protests and call on the security forces to act with restraint. Leaders on all sides must work to reduce the risk of further violence. Only then will it be possible to take vital steps towards dialogue and reconciliation.
Foreign Secretary William Hague
We appeal to all political powers to return to dialogue and negotiations and avoid an escalation of the violence. Every further spillage of blood in Egypt must be prevented.
We urge the interim government and the Egyptian authorities to allow peaceful protests and at the same time we expect from the other forces that they distance themselves from violence, do not call for violence and do not use violence.
Foreign Minister Guido Westerwelle
France condemns the bloody violence in Egypt in the strongest possible terms, and calls for an immediate halt to the crackdown. Foreign Minister Laurent Fabius is taking this matter to UN Secretary-General Ban Ki-moon and to our principal partners so that an international position may be urgently adopted to that effect.
The current situation will not be resolved by force. France calls on all the parties to reject spiralling clashes and to immediately begin a dialogue that includes all Egyptian political forces in order to find a democratic solution to this grave crisis.
French foreign ministry statement
I am deeply pained at what is going on in Egypt, and at the loss of human life there. I was hoping that the squares where the sit-ins took place would empty out once the parties had reached an agreement, and not through the intervention of the police, which doesn't make it any easier to find a solution to the political crisis.
I appeal to all the Egyptian forces to do everything in their power to halt the violence that has erupted there, and to avoid a blood bath. All forces of order must exert the maximum self-control, and everyone must likewise avoid any form of incitement to violence.
Italian Foreign Minister Emma Bonino
Qatar strongly denounces the means by which peaceful protesters in [the] Rabaa al-Adawiya camp and [in] Nahda Square have been dealt with and which led to the killing of several unarmed innocent people among them.
Qatar sees that the secure and safe way to resolve such a crisis is the peaceful manner and the principle of dialogue between the parties who should live together within the framework of political and social pluralism.
Foreign ministry spokesman