KYIV, Ukraine (AP) 鈥 Ukraine rushed reinforcements to its northeastern Kharkiv region on Friday to hold off a Russian attempt to breach local defenses, authorities said, signaling a tactical switch in the war by Moscow that Ukrainian officials had been expecting for weeks.

Kharkiv's regional governor, Oleh Syniehubov, said intense overnight shelling targeted Vovchansk, a city with a prewar population of about 20,000 that is less than 5 kilometers (3 miles) from the Russian border. The barrage, which used powerful guided aerial bombs, artillery, rockets, tanks and mortars, killed at least one civilian and wounded five others, prompting authorities to begin evacuating about 3,000 people.

Then, around dawn, Russian infantry tried to penetrate Ukrainian defenses near Vovchansk, the Ukrainian Defense Ministry said, adding that it had deployed reserve units to fend off the attack.

Russian military bloggers said the assault could mark the start of a Russian attempt to carve out a 鈥渂uffer zone鈥 that President vowed to create earlier this year to halt and other Russian border regions.

By mid-afternoon, Ukrainian troops were still holding firm against the assault, Syniehubov said.

鈥淎ctive combat is ongoing in the settlements located 1-2 kilometers (miles) away from border with Russia,鈥 he told Ukrainian television.

Ukraine previously said it was aware that Russia was assembling thousands of troops along the northeastern border, close to the Kharkiv and Sumy regions. Although Russia's most recent ground offensive had been focused on parts of farther south, Ukrainian intelligence officials said they had expected an attack in the northeast, too. The Kremlin's forces of Kharkiv, Ukraine's second-largest city, in late March.

President said Ukraine's military had anticipated this latest attack and had calibrated its response.

鈥淣ow there is a fierce battle in this direction,鈥 Zelenskyy was quoted as saying by Ukraine鈥檚 public broadcaster Suspilne.

Though Russia likely couldn't capture Kharkiv without a massive buildup of troops and armor, it could compel Ukraine to send more troops to the region, leaving other areas of the country more vulnerable. Forcing Ukrainian authorities to evacuate civilians will also likely cause disruptions and divert resources.

The Russian military could also try to cut key supply routes in the area and try to blockade Kharkiv, which is home to roughly 1.1 million people and is only about 30 kilometers (about 20 miles) south of the border.

The Kremlin's forces are seeking to exploit Ukraine鈥檚 shortages of ammunition and manpower after the flow of Western military aid to Kyiv tapered off in recent months and before arrives. In a post on X Friday, Zelenskyy said: 鈥淣ot all of our partners are currently fulfilling the agreements in a timely manner,鈥 though he didn't specify which.

The Ukrainian army is on the defensive along the roughly 1,000-kilometer (620-mile) front line and is scrambling to build ahead of what officials believe will be a bigger Russian offensive. Ukraine鈥檚 forces are outnumbered in infantry, armor and ammunition.

In the opening days of the war, Russia made a botched attempt to quickly storm Kharkiv but retreated from its outskirts a month later. Seven months after that, Ukraine鈥檚 army in the fall of 2022. The helped persuade Western countries that Ukraine could defeat Russia on the battlefield and merited military support.

In Vovchansk, local officials said the Russian assault had damaged numerous buildings.

鈥淭he entire town is under massive shelling now. It is not safe to stay here,鈥 Vovchansk administration head Tamaz Hambarishvili told Ukraine鈥檚 Hromadske Radio.

The Ukrainian Defense Ministry said fighting against Russian sabotage and reconnaissance groups had continued into the afternoon.

Meanwhile, Russian officials said a Ukrainian long-range drone struck an oil refinery inside Russia on Friday. The drone hit a refinery near the city of Kaluga, southwest of Moscow, setting four oil storage tanks ablaze, according to Vladislav Shapsha, the regional governor. He said there were no casualties.

The Russian Defense Ministry said air defenses downed seven Ukrainian drones early Friday in the Moscow, Bryansk and Belgorod regions.

The attack Friday came a day after one on a petrochemical facility in what appears to have been Ukraine's deepest strike into Russia. A senior official in Russia鈥檚 Bashkortostan region, about 1,300 kilometers (800 miles) from the Ukrainian border, said Thursday's drone strike in the city of Salavat caused a fire at the petrochemical facility.

The Russian Emergencies Ministry said that a pumping station building on refinery land was damaged, but there was no fire. Ukrainian military intelligence refused to comment.

Ukraine has repeatedly targeted refineries, hoping to disrupt the Kremlin鈥檚 war machine. Russia is one of the world鈥檚 biggest oil producers.

___

Follow AP鈥檚 coverage of the war in Ukraine at

香港六合彩挂牌资料. All rights reserved.