LYMAN/BILA TSERKVA, UKRAINE • President Vladimir Putin signed a law to incorporate four partially occupied Ukrainian regions into Russia Wednesday, in what Kyiv called the act of a “collective madhouse” at a time when Russia’s forces have been fleeing from the front lines.

The new law would incorporate around 18% of Ukraine’s territory into Russia, equivalent to the area of Portugal, in Europe’s biggest annexation since World War II.

Russia does not fully control any of the four provinces it claims to have annexed, however, and Moscow has yet to demarcate what it now asserts to be Russia’s new borders.

Ukrainian forces have recaptured thousands of square miles of territory since the start of September, including dozens of settlements in just the past few days.

A map of Russia’s “new regions” that was published by state news agency RIA included the full territory of the Ukrainian provinces, but some parts were shaded and labeled as being under Ukrainian military control.