Gunmen stormed an Egyptian military checkpoint at the weekend and killed six soldiers as militants launched increasingly audacious attacks on the government.

Some of the soldiers were shot while still in their beds on Saturday morning, officials said.

Provincial security chief Major General Mahmoud Yousri told state news agency Mena that the gunmen also planted explosive devices in Shubra al-Kheima near Cairo, but bomb disposal experts managed to defuse two and detonate another in a controlled explosion.

The military immediately blamed the "terrorist" Muslim Brotherhood for the attack.

"How can the (Brotherhood) be accused (a) few minutes after the attack with no evidence or investigation?" asked Amr Darrag, former international chief of the group's now-banned political wing.

Armed forces spokesman Colonel Ahmed Mohammed Ali said the soldiers, of a military police unit, were attacked just after morning prayers.

"These cowardly operations will only increase our determination to continue the war against terrorism," he said.

The military-backed government has blamed a number of recent militant attacks on the Brotherhood, from which coup-toppled president Mohammed Morsi hailed, without presenting much substantive evidence.

Most of the attacks have been claimed by al-Qaida-linked Ansar Beit al-Maqdis, based in the Sinai peninsular.

In shoring up its power, the government has increasingly targeted non-Islamists and those involved in the uprising.

Government officials put the numbers arrested in crackdowns in the past eight months at 16,000 - including 3,000 mid- or senior-level members of Mohammed Morsi's government.