KYIV, Ukraine (AP) — Russia unleashed a series of attacks on Ukrainian rail and oil facilities on Monday, hitting crucial infrastructure far from the front line of its eastern offensive, which Britain says will not has not yet achieved any significant breakthrough.

Meanwhile, two fires were reported at oil facilities in western Russia. It is not known what caused the fires.

While both parties 2 month war Bracing for what could be a tough battle of attrition in the industrial heartland of the country's east, senior US officials have pledged more help to secure Ukraine's victory.

During meetings with President Volodymyr Zelensky in Kyiv on Sunday, the US Secretaries of State and Defense said that Washington had approved a $165 million ammunition sale for Ukraine's war effort, as well as over $300 million in foreign military funding.

"The strategy we have put in place - massive support for Ukraine, massive pressure against Russia, solidarity with more than 30 countries committed to these efforts - is delivering real results," Blinken told reporters in Poland the day after the meeting.

“As far as Russia's war aims are concerned, Russia is failing. Ukraine is succeeding,” he added.

Speaking to senior officials in the Attorney General's Office on Monday, Russian President Vladimir Putin said the United States and its allies had tried in vain to "divide Russian society and destroy Russia from within."

When Russia invaded on February 24, its apparent objective was a lightning offensive that would quickly take the capital and perhaps even overthrow the government in kyiv. But the Ukrainians, aided by western weapons , bogged down Putin's troops and thwarted their push towards kyiv .

Moscow now claims to focus on the eastern Donbass region, but senior military official says he also wants to control southern Ukraine . While both sides have said the campaign in the east has begun, it has yet to gain momentum.

A small group of Ukrainian soldiers holed up in a steelworks in the strategic town of Mariupol are pinning down Russian forces and preventing them from being added to the offensive elsewhere in the Donbass, the British Ministry of Defense said on Monday.

Over the weekend, Russian forces launched new airstrikes on the steelworks in an attempt to dislodge the approximately 2,000 fighters inside. About 1,000 civilians are also sheltering in the steelworks, and the Russian military pledged to open a humanitarian corridor on Monday to allow them to leave.

Mariupol has endured heavy fighting since the start of the war due to its strategic location on the Sea of ​​Azov. In addition to freeing Russian troops, its capture would deprive Ukraine of a vital port and allow Moscow to establish a land corridor to the Crimean peninsula, which it seized from Ukraine in 2014.

But so far, the British Ministry of Defense has said Russia has "not yet achieved a significant breakthrough" since focusing on Donbass. Ukrainian forces repelled numerous assaults last week and "inflicted a significant cost on Russian forces", he said.