* Senior Interior Ministry official killed in Cairo
* Attack coincides with court appearance by ousted leader
* Army chief set to announce candidacy for president soon (Adds details on Mursi trial)
By Michael Georgy
CAIRO, Jan 28 (Reuters) - Two gunmen on a motorbike killed a senior Egyptian Interior Ministry official outside his home in Cairo on Tuesday, security officials said, putting pressure on the military-backed government as it struggles to contain an Islamist insurgency.
The death of General Mohamed Saeed, head of the technical office of the minister of interior, suggested militants were stepping up their campaign against the state at a delicate time in Egyptian politics.
Army chief Field Marshal Abdel Fattah al-Sisi, who toppled president Mohamed Mursi in July, is expected to announce his candidancy for the same post in the coming days, a move that will anger the Muslim Brotherhood to which Mursi belonged.
The Islamist movement accuses Sisi of staging a coup that has undermined democratic gains made since an uprising ousted autocrat Hosni Mubarak in 2011. Hundreds of its supporters were killed in clashes with security forces across Egypt in August.
In the violence since Mursi's ouster, hundreds of members of the security forces have also been killed.
Saeed's assassination came hours before Mursi appeared at a courthouse set up at a Cairo police academy to face charges of kidnapping and killing policemen after a 2011 jailbreak.
Mursi, who already faces charges in three other cases, will not have the opportunity to scream slogans against Sisi and the army-backed government, as he did in previous court sessions.
This time he is being held in a glass cage with a sound system controlled by the court, another example of the crackdown on dissent which has drawn criticism from human rights groups.
The Interior Ministry confirmed Saeed's killing. He was an aide to Interior Minister Mohamed Ibrahim, who survived an assassination attempt last year.
Political violence has hit investment and tourism hard in Egypt, which is of strategic importance because of its peace treaty with Israel and control of the Suez Canal.
Militant groups based in the largely lawless Sinai Peninsula have killed hundreds of police and soldiers since Mursi's downfall, but the Islamist insurgency appears to be taking root beyond the region that borders Israel and the Gaza Strip.
It took autocrat Hosni Mubarak several years to end an Islamist insurgency in the 1990s.
Last week, six people were killed in a wave of bomb attacks targeting policemen in Cairo. And a Sinai-based militant group brought down an army helicopter with a missile, killing five soldiers. (Writing by Michael Georgy; Editing by Mike Collett-White)