An Egyptian Army officer detains a man near the presidential palace. (AP Photo/Nasser Nasser)

Egypt's Republican Guard, an army faction whose job includes protecting the president, deployed tanks around Cairo's presidential palace overnight. The move was seen as a response to clashes between protesters who support and oppose President Mohamed Morsi's recent moves to increase his own power. We explain the political crisis here.

The return of tanks to Cairo's streets, less than two years after the army deployed during the protests that culminated in Hosni Mubarak's resignation, has raised the stakes of this latest crisis, implicitly signaling the army's willingness to intervene – though it's still not clear on whose side.

"For a moment, Cairo seemed to be holding its breath," Abigail Hauslohner and Stephanie McCrummen report in today's Post.

Though many demonstrators had left the wealthy neighborhood around the presidential palace by early afternoon, the most hardened remained in streets now strewn with broken glass and rocks and lined with smashed cars.

Wednesday’s violence was the fiercest of the country’s two-week-old political crisis, with demonstrators pelting each other with stones and molotov cocktails and wielding sticks and clubs, significantly intensifying the pressure on Egypt’s embattled new government.

Here are a few more photos of the tanks' deployment. Some of the army troops are reportedly clearing protesters from the area around the presidential palace. I visited Cairo in August 2011, when most military vehicles and troops had been pulled back but a few remained, and to my non-veteran eyes, their presence felt even more unsettling – even creepy – than I'd anticipated. Maybe Cairenes are more accustomed to this sight, but it's worth pausing for a moment to imagine what the sudden appearance of tanks, in the middle of a crisis, when it's not clear whom the army supports, would feel like for the city's millions of inhabitants.

Egyptians walk past army tanks deployed near the presidential palace. (MAHMOUD KHALED/AFP/Getty Images)

Pedestrians walk past a deployed tank. (AP Photo/Hassan Ammar)

Supporters of Egypt's Islamist President Mohamed Morsi carry a post bearing his face. (MAHMOUD KHALED/AFP/Getty Images)