A bomb blast near Egypt's foreign ministry killed two police officers and wounded several others on Sunday, the Interior Ministry said, in the most serious attack in Cairo in almost three months.

There was no immediate claim of responsibility for the attack which killed two police lieutenant colonels. But the operation resembled ones carried out by Islamist insurgents seeking to topple the U.S.-backed government.

Egypt has faced rising Islamist militant violence since the army deposed President Mohamed Mursi last year and cracked down on his Muslim Brotherhood movement.

The challenge has become more complex since Islamic State militants seized parts of Iraq and Syria in June and declared a caliphate, inspiring other militant groups including some based along Egypt's border with chaotic Libya.

Islamic State established ties with Sinai-based Ansar Bayt al-Maqdis and has been coaching Egypt's most lethal militant organisation, security officials and a commander in the group told Reuters.

Smoke was rising and people ran after Sunday's blast along a sidewalk in the neighbourhood of Boulaq bu Eila, just behind the Foreign Ministry, which is located in a high rise building beside the Nile.

The blast caused a tree to fall on a car. Blood stained a busy intersection beside a crowded market.

While the death toll was low, any attack in the capital is bound to cast doubt over the security forces, who have vowed to end Islamist militant bloodshed that has hammered the tourism industry, a pillar of the economy.

President Abdel Fattah al-Sisi, who as army chief removed the Muslim Brotherhood from power, has repeatedly expressed concerns about militancy in Egypt and other parts of the Middle East. - Reuters