Masked gunmen have opened fire on an army bus in the Egyptian capital Cairo, leaving an officer dead and three soldiers wounded, a military source says.

The unnamed military source said on Thursday that the gunmen riding a motorcycle attacked the bus in the Amiriya neighborhood in Cairo, Reuters reported.

The Egyptian army source accused the Muslim Brotherhood of being behind the attack, saying the atrocity left “the Warrant Officer Yusri Mahmoud Mohamed Hassan” dead and three others injured.

Egypt has seen a sharp rise in drive-by shootings and attacks targeting police and the military since last July, when the military ousted the country’s first democratically-elected president, Mohamed Morsi.

According to reports, at least 250 police and soldiers have been killed in armed attacks since then.

Earlier this month, gunmen killed a police officer as he was riding his motorcycle in the Nile Delta city of Mansoura. A fatal attack by masked men on a security checkpoint in the al-Wassta District of Bani Suief in January also claimed the lives of five police officers.

In December last year, a car bombing left nearly 16 people, most of them policemen, dead in Mansoura.

The Egyptian interim government accused the Muslim Brotherhood of engineering the attack, calling the group a “terrorist organization.”

The Brotherhood, however, condemned the bombing, describing it as a “direct attack on the unity of the Egyptian people.” The group has also called for the perpetrators to be brought to justice.