KYIV, Ukraine (AP) Russian President Vladimir Putin acknowledged Wednesday that his special military operation in Ukraine is taking longer than expected but said it has succeeded in seizing new territory and added that his countrys nuclear weapons are deterring escalation of the conflict.

Of course, it could be a lengthy process, Putin said of the more than 9-month-old war that began with Russias invasion Feb. 24 and has displaced millions from their homes, and killed and wounded tens of thousands. Despite its length, he showed no signs of letting up, vowing to consistently fight for our interests and to protect ourselves using all means available. He reiterated his claim that he had no choice but to send in troops, saying that for years, the West responded to Russias security demands with only spit in the face.

Speaking in a televised meeting in Russia with members of his Human Rights Council, Putin described the land gains as a significant result for Russia, noting that the Sea of Azov has become Russias internal sea. In one of his frequent historic references to a Russian leader he admires, he added that Peter the Great fought to get access to that body of water.

After failing to take Kyiv due to fierce Ukrainian resistance , Russia seized broad swaths of southern Ukraine at the start of the invasion and captured the key Sea of Azov port of Mariupol in May after a nearly three-month siege. In September, Putin illegally annexed four Ukrainian regions even though his forces didnt completely control them: Kherson and Zaporizhzhia in the south, and Donetsk and Luhansk in the east. In 2014, he had illegally annexed Ukraines Crimean Peninsula.

In response to an increasing influx of advanced Western weapons, economic, political and humanitarian aid to Kyiv and what he saw as Western leaders inflammatory statements, Putin has periodically hinted at his potential use of nuclear weapons. When a member of the Human Rights Council asked him Wednesday to pledge that Russia would not be the first to use such weapons, Putin demurred. He said Russia would not be able to use nuclear weapons at all if it agreed not to use them first and then came under a nuclear strike.

If it doesnt use it first under any circumstances, it means that it wont be the second to use it either, because the possibility of using it in case of a nuclear strike on our territory will be sharply limited, he said.

Putin rejected Western criticism that his previous nuclear weapons comments amounted to saber-rattling, claiming they were not a factor provoking an escalation of conflicts, but a factor of deterrence.

We havent gone mad. We are fully aware of what nuclear weapons are, Putin said. He added, without elaborating: We have them, and they are more advanced and state-of-the-art than what any other nuclear power has.

In his televised remarks, the Russian leader didnt address Russias battlefield setbacks or its attempts to cement control over the seized regions but acknowledged problems with supplies, treatment of wounded soldiers and limited desertions.

Russian troops have withdrawn not only from the Kyiv area and around the countrys largest city, Kharkiv, but from a large part of the Kherson region. Another problem for Putin are attacks this week against air force bases deep inside Russia. He put much of the country, especially border areas, on security alert recently, and fresh signs emerged Wednesday that Russian officials are strengthening border defensive positions.

In the Kursk region bordering Ukraine, the governor posted photos of new concrete anti-tank barriers known as dragons teeth in open fields. On Tuesday, the governor had said a fire broke out at an airport in the region after a drone strike. In neighboring Belgorod, workers were expanding anti-tank barriers and officials were organizing self-defense units. Belgorod has seen numerous fires and explosions, apparently from cross-border attacks, and its governor reported Wednesday that Russias air defenses have shot down incoming rockets.

In brazen drone attacks, two strategic Russian air bases more than 500 kilometers (300 miles) from the Ukraine border were struck Monday. Moscow blamed Ukraine, which didnt claim responsibility.

Moscow responded with strikes by artillery, multiple rocket launchers, missiles, tanks and mortars at residential buildings and civilian infrastructure, worsening damage to the power grid. Private Ukrainian power utility Ukrenergo said temperatures in eastern areas where it was making repairs had dropped to as low as minus 17 degrees Celsius (near zero Fahrenheit).

At his meeting, Putin discussed the mobilization of 300,000 reservists that he ordered in September to bolster forces in Ukraine. He said only about 150,000 have been deployed so far to combat zones and the rest are still undergoing training. Addressing speculation that the Kremlin could be preparing another mobilization, Putin said: There is no need for the Defense Ministry and the country to do that.

In other developments:

Ukraines presidential office said Russian forces overnight struck nine regions in the east and south, and resumed using Iranian-made Shahed drones after supply difficulties. First appearing in Ukraine in late August, the Shahed drones were Moscows weapon of choice to cause power blackouts. Britains Ministry of Defense said last month Russia was running out of the drones but would probably seek replacements.

In the city of Kherson, a 43-year-old waterworks employee was killed when Russian shelling ignited a fire and damaged residential buildings, the presidential office said. In the Donetsk region, Moscow is pressing an offensive near Bakhmut and Avdiivka, with some 20 towns and villages under fire, the General Staff of the Armed Forces of Ukraine said. Ukrainian President Volodymr Zelenskyy said four Kherson police were killed dealing with mines Russian forces left behind when they retreated.