Moscow’s Pushkin Museum of Fine Arts expansion project, one of Russia’s most prominent and contentious building schemes, has spiraled into disarray. Since Foster + Partners’ winning plans to expand and modernize the 101-year-old institution were originally approved in 2009, the development has been confronted with a series of delays including disputes between officials and preservationists. Now, to cap it off, the firm has officially resigned from the project.

Recently, Pushkin’s chief architect Sergei Kuznetsov publicly proposed that Norman Foster take a more hands-on role and demonstrate his commitment to the $670 million project by traveling to the Russian capital within a month. Kuznetsov’s ultimatum specified that “if Sir Foster, for one reason or another, refuses to participate further in the work, then, most likely, a competition will be held to choose another team, possibly of Western architects.”

In response, Foster + Partners issued a statement revealing that the firm had already sent a resignation letter in June to former museum director Irina Antonova, who stepped down in July after running the museum for more than 50 years. The statement claimed that the museum has not involved the firm in the development of the project over the last three years, despite several attempts to continue working with the institution. In a statement sent to The Art Newspaper, the firm said that it had “formally resigned from the Pushkin Museum project and stipulated that their name could not be used in conjunction with the project.”

Scheduled for completion in 2018, Foster’s design involved forming a museum complex encompassing the Pushkin Museum and overhauling twelve neighboring mansions. The “Museum Town,” first envisioned by Antonova in 2006, would incorporate a concert hall, a library, and underground facilities. Antonova had asked Foster to design a high quality, 21st century facility.