Egyptian President Mohammed Mursi has warned that continuing unrest is "threatening to paralyze the country", BBC News reports.

In a speech marking his first year in office, Mursi acknowledged making some "mistakes" and offered opponents a say in amending the new constitution. But the president also threatened those he saw as conspiring against him and trying to "sabotage" democracy.

Troops have been deployed in cities across the country ahead of planned weekend protests demanding his removal.

Ahead of Mursi's speech, deadly clashes broke out in the northern city of Mansoura. Two people were killed and 170 injured in fighting between supporters and opponents of the government, a health ministry spokesman said.

In his two-hour televised address on Wednesday, June 26 evening, Mursi defended his performance, admitting errors and promising immediate and radical reforms to address them.

"I was right in some cases, and wrong in other cases," he said. "I have discovered after a year in charge that for the revolution to achieve its goals, it needs radical measures."

He apologized for the fuel shortages that have caused long lines at petrol stations and angered many Egyptians, and also for failing to involve the nation's youth enough.

But despite Mursi's initial conciliatory tone, the speech swiftly moved into a condemnation of those he blamed for Egypt's problems, the BBC says.

"I took responsibility for a country mired in corruption and was faced with a war to make me fail," he said, naming several officials he believed wanted to "turn the clock back" to the Mubarak era, including politicians, judges and a journalists.

“Political polarization and conflict has reached a stage that threatens our nascent democratic experience and threatens to put the whole nation in a state of paralysis and chaos,” he warned. "The enemies of Egypt have not spared effort in trying to sabotage the democratic experience."

The president said he would invite party leaders to meet on Thursday to choose a chairman for a committee that will prepare amendments to the constitution, approved in a referendum last year amid protests by secularists, liberals, women and minorities. He also said he was forming a committee of leading public figures to promote national reconciliation.

"I say to the opposition, the road to change is clear," he added. "Our hands are extended." Anti-government supporters had gathered in the capital's Tahrir Square and outside the defense ministry ahead of Mursi's speech.