Key political factions in and around Egypt are trying to prevent escalation caused by shootings that left dead as many as 40 supporters of ousted president Mohamed Morsi.
One police officer was among those killed during a sit-in in Cairo on Monday. Reports indicate Egyptian police and military troops opened fire on the group of protesters supporting Morsi, who served as the country's first democratically elected leader since the rule of Hosni Mubarak, before being ousted from power last week.
Hamas, the militant political party in the neighboring Gaza Strip, condemned the attacks, adding its "voices of pain and grief" for the deaths, according to a spokesman.
Hamas is an offshoot of Morsi's conservative Muslim Brotherhood, which was slowly moving into more positions of power in Morsi's government before he was forced from office on July 3. The Daily Star of Lebanon reports the Muslim Brotherhood said the protesters were massacred. Some witnesses at the scene say the shooting was conducted by a group of thugs, and the police and troops only fired tear gas and warning shots.
Mohamed ElBaradei, a prominent liberal leader, has called for an independent review into the killings, the Daily Star reports.
The governments of Qatar, Turkey and the U.S. all decried the incident, highlighting fears that further violence will escalate an already tense environment in Egypt.
"I strongly condemn the massacre that took place at morning prayers in the name of basic human values," said Turkish Foreign Minister Ahmet Davutoglu in a tweet. "A political normalization process that respects the will of the Egyptian people must begin."
British Foreign Secretary William Hague said there is "an urgent need for calm and restraint."
Wealthy Gulf nation Qatar, a known supporter of Morsi's government, expressed "great concern" over the incident, according to an unnamed official quoted in the Qatar News Agency.
U.S. Secretary of State John Kerry said he is "deeply troubled by the violence across Egypt," in a statement on Saturday, and rejected calls that the U.S. is supporting any particular side.
"We strongly condemn any and all incitement to violence or attempts to divide and provoke, rather than unite, all Egyptians," he said.
"We firmly reject the unfounded and false claims by some in Egypt that the United States supports the Egyptian Muslim Brotherhood or any specific Egyptian political party or movement," he added. "The United States has always been and remains committed to the democratic process, not to any party or personality."
Gen. Martin Dempsey, chairman of the Joint Chiefs, said the turmoil in Egypt is evidence that "democracy takes a while to stick," while speaking in a lengthy interview with CNN recorded July 3. The future of the Egyptian government "is for them to decide," he said.