KYIV, Ukraine (AP) — Russian President Vladimir Putin doubled down Wednesday on his faltering invasion by declaring martial law in four illegally annexed Ukrainian regions and setting the stage for draconian new restrictions and crackdowns throughout Russia. The drastic escalation appeared to be prompted by the threat of more stinging battlefield defeats, sabotage and troubles with his troop mobilization.

The order belies the Kremlin's attempts to portray life in the annexed regions as returning to normal, with the latest example the removal of civilian leaders, the installation of a military administration and a mass evacuation in Kherson.

With a Ukrainian counteroffensive grinding toward Kherson, the battle for the annexed southern city of more than 250,000 people, key industries and a major port is a pivotal moment for Ukraine and Russia heading into winter, when front lines could become largely frozen for months.

In announcing martial law, effective Thursday, Putin told his Security Council, “We are working to solve very difficult large-scale tasks to ensure Russia’s security and safe future.”

It was Putin’s latest attempt to solidify control of not only the annexed regions but his entire country as he faces threats not only from the largely successful Ukrainian counteroffensive, but sabotage of a strategically important bridge linking Russia with Crimea, assassinations of Kremlin-installed officials in Kherson and chaos and mistakes in his partial troop mobilization.

Putin’s martial law declaration authorized creation of territorial defense forces in the annexed regions of Kherson, Donetsk, Luhansk and Zaporizhzhia, along with the potential impositions of curfews, restrictions on travel and public gatherings, tighter censorship and broader law enforcement powers.

In a potentially ominous move, Putin’s order opens the door for restrictive measures to be extended across Russia. That may lead to an even tougher crackdown on dissent and freedom in Russia, where authorities have dispersed antiwar protests and jailed people for making statements or providing information about the fighting that differs from the official line.

The severity of restrictions inside Russia depends on proximity to Ukraine, covering freedom of movement and other security steps.

In the Kherson region, Ukrainian forces have pushed back Russian positions on the west bank of the Dnieper River. By pulling civilians out and fortifying positions in the region's main city, which backs onto the river, Russian forces appear to be hoping that the wide, deep waters will serve as natural barrier against the Ukrainian advance.

A trickle of evacuations from the city in recent days has become a flood. Local officials said Wednesday that 5,000 had left the city already out of an expected 60,000. Russian state television showed residents crowding on the Dnieper’s banks, many with small children, to cross by boats to the east — and, from there, deeper into Russian-controlled territory.