At least six people were killed Thursday in Egypt’s capital Cairo in a bomb attack as security forces arrived at a building where suspected militants were hiding.

Sources told Reuters news agency that the bomb exploded as the police arrived in their vehicles in front of a building where suspected militants were holed up.

#pts pic from t/bomb that was targeted at a passing police vehicle thrown i/t street from 4th floor #Giza,#Egypt - pic.twitter.com/CDzKRsRMiu

— Karina Loren (@miskelayla) January 21, 201

"Six people have been killed in the blast, including three policemen. The others include a civilian and two unidentified men," a police officer told AFP. At least 15 others were wounded in the attack.

The Interior Ministry released a statement confirming the death of the three Egyptian policemen in the blast. The ministry blamed the attack on members of the banned Muslim Brotherhood party, the political movement of former President Mohamed Morsi, who was ousted by a military coup in 2013.

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The al-Haram neighborhood where the attack happened is known to have sympathizers of Morsi and his Muslims Brotherhood party.

In the aftermath of the 2013 coup, the area saw regular clashes between police and locals protesting the takeover by then head of the armed forces Abdel-Fattah el-Sissi, who is now the president.

The attacks come a few days before the anniversary of the Jan. 25 revolution in Egypt that ousted longtime dictator Hosni Mubarak in 2011.

#Cairo feels extremely tense in run up to Jan25 anniversary w/ 1000sof police flat raids-&now blast reportedly killing 6ppl includ. officers

— Bel Trew - بل ترو (@Beltrew) January 21, 201

But the country has seen an insurgency against the coup government and Sissi’s regime in the eastern Sinai region. Several extremist groups including the Islamic State group are operating in the country.

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Over the past few years, several attacks have occurred in the capital against tourists and foreign embassies.

On Friday, three foreign tourists were wounded after two armed assailants attacked a hotel in the Egyptian Red Sea resort town of Hurghada. That attack was claimed by the Islamic State group affiliate in Egypt.

Egypt regime thinks the revolution happened because of some foreign NGOs and activists in downtown Cairo. https://t.co/dEemj79t09

— The Big Pharaoh (@TheBigPharaoh) January 20, 201

Last week, the government warned against protests marking the anniversary of the revolution as many local activists and rights groups have been calling for action against Sissi’s administration.

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Since the ouster of Morsi in the summer of 2013, at least 16,000 people have been arrested and more than 2,500 killed. More than 700 people were sentenced to death in April 2014. Morsi was sentenced to death over spying charges and a jail break.

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