CAIRO - Deadly clashes erupted in Egypt Saturday as rival demonstrations were held on the anniversary of the 2011 revolt that toppled Hosni Mubarak, underscoring the country’s violent polarisation three years after the Arab Spring.

Thousands of demonstrators in Cairo’s Tahrir Square chanted slogans backing military chief General Abdel Fattah al-Sisi and called for Muslim Brotherhood members to be killed, as Islamists staged their own smaller rallies elsewhere, sparking clashes with police. The divisions underscored the bitter polarisation since the 2011 revolt, in which Egyptians of all political stripes united to demand the end of Mubarak’s three-decade rule, galvanising the Arab Spring.

Nine people were killed during anti-government marches while thousands rallied in support of the army-led authorities. Four protesters were killed in different parts of the capital, where armoured personnel carriers were deployed to try and keep order, and anyone entering Tahrir had to pass through a metal detector.

Egypt was already on edge after four bombs exploded in Cairo on Friday, including a massive blast outside police headquarters. The attacks, which were claimed by a Sinai-based extremist group, killed six people. Hours before Saturday’s rallies, a small bomb outside a police training centre in north Cairo wounded one person, the health ministry said.

And a car bombing at a police base in the canal city of Suez wounded at least four people, security officials said.

An Al-Qaeda-inspired group - Ansar Beit al-Maqdis, or Partisans of Jerusalem - claimed responsibility for Friday’s bombings, all of them targeting police, and urged ordinary Egyptian “Muslims” to stay away from police buildings.

Kidnappers seized Egypt's cultural attache and three other embassy staff in the Libyan capital on Saturday a day after a group snatched another Egyptian official in the city.

Meanwhile, the toll from clashes in the south and west rose to 154 dead and 463 wounded, a further sign of the chronic instability that has plagued Libya since the 2011 uprising ousted dictator Moamer Kadhafi. The four diplomats were kidnapped early on Saturday morning, a Libyan foreign ministry spokesman said,

"The cultural attache and three other staff were kidnapped in Tripoli," Said Lassoued told AFP.

The abductions came a day after an unknown group seized an administrative adviser at Egypt's embassy, and despite Libya's announcement of "reinforced security measures" there. Foreigners have been targeted several times in recent weeks: two Italians were seized last week in east Libya and a South Korean trade representative was released by security forces on Wednesday, three days after he was abducted in Tripoli. Prime Minister Ali Zeidan was himself briefly abducted by a militia last October. A Libyan security official would not rule out that Friday's kidnapping of the Egyptian was a response to the arrest in Egypt on Friday of a prominent former rebel commander who fought in the uprising.

Shaaban Hadeia, head of the Operations Centre of Libya's Thuwar (revolutionaries), was arrested in Alexandria, the source added. The Operations Centre had posted on Facebook that there could be a "possible reaction from the thuwars". But one of the group's leaders, Adel al-Ghariani, told AFP they were not involved in the kidnappings and called for Hadeia's release.

The presidency of the General National Congress, Libya's highest political authority, also ordered its mission in Cairo to demand an explanation for the ex-rebel leader's arrest and to seek his release. Cairo has yet to confirm his detention. Libya has struggled to integrate into the security forces rebel groups that helped topple Kadhafi. Some militias have carved out their own fiefdoms, each with its own ideology and regional allegiances.