The U.S. and British foreign ministers met President Volodymyr Zelenskiy on Wednesday on a visit interrupted by air raid warnings, unveiling new support but no breakthrough on the long-range strikes into Russia desperately sought by Ukraine, Reuters reported.

U.S. Secretary of State Antony Blinken and British foreign minister David Lammy, in Kyiv at a critical juncture in Ukraine's struggle against Russia, said they talked about Ukraine's war goals and what they could do to help.

"Among other things, we discussed long-range fires, but a number of other things as well. And as I said at the outset, I'm going to take that discussion back to Washington to brief the president on what I heard," Blinken told reporters.

Zelenskiy has been pleading with Kyiv's allies for months to let Ukraine fire Western missiles including long-range U.S. ATACMS and British Storm Shadows deep into Russian territory to limit Moscow's ability to launch attacks.

"We are listening carefully and, of course, we are having discussions on a range of issues, including the military equipment that Ukraine needs to win," Lammy told a news conference alongside Blinken and Ukraine’s Foreign Minister Andrii Sybiha.

The British foreign minister suggested those discussions could continue for a few more weeks, a remark that will disappoint Ukrainians hoping the West would quickly discard fears of escalation.

Ahead of the news conference, Zelenskiy was asked whether he was optimistic the United States and Britain would greenlight deeper strikes into Russia, and he quipped that it depended instead on the "optimism" of Ukraine's partners, read the report.

"Let's count on some strong decisions at least. For us it's very important for today," he told reporters in Kyiv.

In a comment posted on his Telegram channel, Zelenskiy described the talks as "long and meaningful".

"All the key issues were discussed," he wrote.

"What's important is that all the Ukrainian arguments were heard. And that concerns long-range weaponry, supplying our front-line brigades and the general strategy of moving strategically towards a just peace."

There is nervousness in Washington and some European capitals that lifting the restrictions on long-range attacks could provoke Russia towards a direct conflict with the West, at the same time as a recognition that Ukraine needs more help if it is to swing the war in its favour, Reuters reported.

The speaker of Russia's lower house of parliament, Vyacheslav Volodin, said Moscow would consider the United States and its allies to be parties to the war if they allowed Kyiv to use long-range weapons to strike deep in Russia.

Overnight, U.S. President Joe Biden suggested there was room for compromise, saying his administration was "working that out now" when asked if the United States would lift the restrictions on the use of long-range weapons.

The air raid alert sounded twice during Blinken and Lammy's visit to Kyiv, before and after the news conference. A wreath-laying ceremony they were due to attend was cancelled.

Both alerts appeared to have been sounded over ballistic missile threats, but it was unclear what any missile had been targeting or what happened to the missiles.

Blinken announced more than $700 million in support for Ukraine. Lammy said Britain would provide a further 600 million pounds ($781 million).

More than 2-1/2 years since the invasion, Russian forces are inching forward in the east as Kyiv's forces try to hold a pocket of land they seized in western Russia in a surprise incursion last month.

After making rapid progress initially, Ukrainian advances have stalled, and on Wednesday a senior Russian commander said his forces had taken back control of about 10 settlements.

Ukraine has not commented on the latest Russian reported gains. Reuters was not able to independently verify battlefield developments, read the report.

Later this month, Zelenskiy travels to the United States and will present a plan to Biden and his two potential successors in November's presidential election that he hopes will bring the end of the war closer.

Unidentified assailants opened fire on a polio vaccination team in northwestern Pakistan on Wednesday, killing one of those handing out doses and one policeman escorting him, police said.

The attack in the region bordering Afghanistan comes two days after Pakistan launched its latest national campaign to stamp out the virus, which still poses a health threat in the South Asian nation, although mostly eradicated elsewhere, Reuters reported.

"Unidentified armed men opened fire on polio vaccination team in a subdivision of Bajaur tribal district as they were on the vaccination campaign," district police officer Waqas Rafique told Reuters.

No group has claimed responsibility, but previously Islamist militant groups in the region have claimed similar attacks on polio teams, falsely portraying the inoculation campaigns as a Western conspiracy to sterilise children.

Pakistan began its latest national campaign earlier this week, aiming to administer the vaccine to up to 30 million children, the prime minister's office said.

Pakistan and Afghanistan are the only two countries in the world still struggling to eradicate polio, read the report.

A local police union group called for a strike by policemen and a boycott of security duties for the vaccination campaign in the Bajaur district following the killing of their colleague.