Lawmakers join Elizabeth Warren's call for US to 'step in' on illegal Airbnb hotels

Exclusive: a joint letter marks the escalation of a growing campaign for Airbnb to eliminate illegal hotels that take affordable housing off the market

Airbnb is facing renewed calls for a federal investigation from more than a dozen US cities, boosting senator Elizabeth Warren's efforts to force the popular home-sharing startup to release data on its affordable housing impact.

A coalition of American lawmakers, including leaders from New York, San Francisco, Seattle, St Louis and Portland, urged the Federal Trade Commission (FTC) on Thursday to "help cities to protect consumers" and "study the extent to which the [short-term rental] industry is facilitating commercial operations".