Crews expected to return at night to continue removal of 20-metre stretch of wall to make way for luxury block of flats

Hundreds of protesters have gathered at the longest remaining stretch of the Berlin Wall for an angry standoff with developers who removed a small section of the structure to make way for a luxury block of flats.

About 1.5 metres (5ft) of the East Side Gallery was taken down before protests brought an end to the work as police determined it was unsafe to continue.

A further 18.5-metre stretch is due to be dismantled to allow access between the 36-flat complex and the banks of the river Spree, which flows adjacent to the 1.3km length of wall.

Protesters brought in a mock wall section to try to fill in the gap. Some carried banners, one of which read: "Mr Wowereit, don't tear down this wall" – an appeal to Berlin's Social Democrat mayor, Klaus Wowereit, and a veiled reference to a 1987 speech made at the wall by Ronald Reagan in which the then US president urged the Soviet leader: "Mr Gorbachev, tear down this wall."

Another protester's sign read: "Does culture no longer have any value?"

Most of the Berlin Wall, which divided East and West Germany for 28 years, was torn down and carted off to museums, ground into grit for autobahns or sold to tourists following the collapse of the iron curtain, but the section now under dispute was turned into an open-air gallery.

About 120 international artists were invited to plaster it with colourful murals, as the strip of wall carried none of the colourful graffiti that had covered the western side. In 2009 the murals were renovated at a cost of €2m (£1.7m).

The murals include depictions of the former Soviet and East German leaders Leonid Brezhnev and Erich Honecker in a passionate clinch, and a Trabant car bursting through the wall.

The piece removed by a crane on Friday bore a mural depicting the Brandenburg Gate, which was sealed off by the wall for years but is now Berlin's most popular landmark. One Twitterer remarked: "No one was this upset last time they started tearing down the Berlin Wall."

By Friday afternoon more than 30,000 people had signed a petition on change.org calling for the project to be stopped. Protesters vowed they would return for what is the latest battle to reclaim Berlin from developers. Crews are expected to return during night-time hours to continue the demolition.