A homemade bomb has exploded in front of the Israeli embassy in Cairo, security sources and the website of the state-run Al-Ahram newspaper has said.

Security sources said the explosion on Tuesday targeted a police car, rather than the embassy itself, and did not cause any injuries.

The office has not been used by Israeli diplomats for at least two years, following a September 2011 attack on the embassy, the Reuters news agency reported.

Earlier on Tuesday, police shot dead a man suspected of being involved in a January bomb attack against Cairo’s police headquarters, the interior ministry said.

The bombing in the heart of the capital, one of many attacks targeting security forces since the ousting of President Mohamed Morsi by the military in July, had killed four people.

Mohamed al-Sayed Mansour al-Toukhi was killed in a gun battle with policemen when they came to arrest him in an eastern Cairo neighbourhood, the ministry said.

His killing comes a day after police said they had arrested a man suspected of being involved in one of the four bombings on January 24 that rocked Cairo a day before the third anniversary of the revolt that toppled Hosni Mubarak in 2011.

An al-Qaeda inspired group, Ansar Beit al-Maqdis, had claimed the bombing of the police headquarters, the AP news agency reported.

The group has also claimed most of the deadliest attacks in Egypt since Morsi’s overthrow, saying they were carried out as revenge against an ongoing government crackdown on his supporters.

Amnesty International says more than 1,400 people have been killed in the crackdown and thousands jailed.

Egyptian prosecutors meanwhile referred to trial four suspected al-Qaeda members, including a Kurd, accusing them of planning attacks against the French and American embassies in Cairo, state news agency MENA reported.

The four are also accused of setting up a terrorist group to attack police and army personnel and Coptic churches, and of providing al-Qaeda fighters in Pakistan with information about Egyptian troops in the restive Sinai Peninsula, MENA said.

(Al Jazeera and agencies – www.aljazeera.com)