News: the iconic 1920s Moscow home of Russian avant-garde architect Konstantin Melnikov is showing signs of serious structural damage as work continues on a large complex next door, warn heritage experts and international architects including Rem Koolhaas and Álvaro Siza.

The cylindrical Melnikov House, located on Krivoarbatsky Lane off the Arbat pedestrian strip, has developed "numerous new cracks" and accrued damage to its foundations as a result of the construction of a mixed-use scheme nearby, according to an appeal addressed to Russian president Vladimir Putin and posted on the website of Moscow-based preservation watchdog Archnadzor last week.

The risk of losing the "masterpiece of twentieth century world architecture", which was designed by Melnikov as a home and studio, had "grown significantly" said the post, as reported in the New York Times.

The architect's granddaughter and current occupant of the house, Ekaterina Karinskaya, believes the greatest threat to the physical condition of the house is the three-level underground parking garage for the building planned behind the house.

The walls of the garage would block the path of groundwater and flood the Melnikov House, she explained in a report posted on the US website of international heritage watchdog Docomomo.

"All of this is being done in order to simply destroy the house," said Karinskaya. "They cannot just knock it down because it will draw a widely negative response. So they have dug from two sides, setting off processes underneath in the soil.

"Now they will build a dam so that the house would crumble down by itself. And once that happens, they will say 'well, what did you expect, [the house] is old… it's over now, it's dead'."

Another open letter called for the preservation of the house as a public museum to house all Melnikov's archival material, most of which is currently inaccessible to researchers.

The letter, whose signatories included architects Rem Koolhaas, Álvaro Siza and Arata Isozaki, also demanded "fair compensation of the Melnikov family for their efforts to preserve it".

Architects Peter Eisenman, Kenneth Frampton, Steven Holl, Alberto Pérez‐Gómez and Bernard Tschumi were also among the letter's signatories.

Moscow's expansion continues apace with a proposal to build a new district around manmade waterways and the recently completed skyscraper Mercury City, which last year usurped Renzo Piano's The Shard as the tallest building in Europe – see all news and architecture from Moscow.

In New York this week the Museum of Modern Art announced plans to demolish the American Folk Art Museum next door, just 12 years after it was completed by US architects Tod Williams and Billie Tsien.

Top photograph is by dbasulto and lower photograph is by qwz.