Zelensky was speaking hours after confirming that the United States and Britain had still not authorised Kyiv to use such weapons in this way.
But in his evening address Saturday he said: "We are convincing our partners -- and we will continue to talk about this next week -- that Ukraine needs full long-range capabilities."
During his visit to Washington, Zelensky is due to set out his plan to end the war in talks with Biden, Vice President Kamala Harris -- and with Republican presidential candidate Donald Trump.
Kyiv has for weeks been pressing the West to allow it to use Western-supplied long-range weapons to strike targets inside Russia.
It says that could change the course of the war, two and a half years after Moscow invaded its neighbour.
"Neither America nor the United Kingdom gave us permission to use these weapons on the territory of Russia, on any targets, at any distance," Zelensky told reporters late on Friday.
"I think they are worried about an escalation."
Russian President Vladimir Putin has warned that if Ukraine uses long-range weapons supplied by the West to strike targets inside Russian territory, that would signify NATO countries were also at war with Russia.
But Zelensky hinted he had not given up hope that Biden might yet be persuaded.
"We have had some decisions in the history of our relationship with Biden -- very interesting and difficult dialogues," the Ukrainian leader said. "He later changed his point of view."
A close adviser to Biden said this month he would use his remaining time in office to "put Ukraine in the best possible position to prevail".
- November summit -
Zelensky will travel to the United States after a summer of intense fighting.
Moscow's forces have been advancing in eastern Ukraine, while Kyiv has held onto swathes of Russia's Kursk region for weeks.
The Russian army is now around 10 kilometres (six miles) away from the eastern Ukrainian hub of Pokrovsk, to where Kyiv has rushed people evacuated from frontline areas.
The war has dragged on for almost 31 months and efforts to end fighting have so far proved unsuccessful.
Zelensky repeated that Ukraine was "ready" to invite Russia to a second international peace summit in November "because all our allies, including our closest ones" said Russia should be there.
The November summit would be "the foundation for talking in any format with Russia", he added.
But Russia said on Saturday it would not take part in such a summit and repeated Putin's conditions that Moscow would only come to the table if Kyiv surrendered four of its regions.
- Kamala, Trump meeting -
Zelensky said he was taking into account that "we will have a very different situation in November" after the US election.
He planned to meet Harris to "see what she thinks about the victory plan" and "definitely" encounter Trump.
Harris and Trump are the rival candidates in the knife-edge US presidential election.
Zelensky is expected to meet Trump on September 25 or 26.
While Harris has indicated that she will continue Biden's policies of backing Ukraine, Trump refused in a recent election debate to take sides over the war.
Kyiv is concerned that if he wins a second term Washington could weaken its commitment to Ukraine.
Trump has been highly critical of the billions of dollars Washington has provided to Kyiv in aid.
Zelensky also dismissed peace proposals put forward earlier this year by China and Brazil -- both of whom have friendly ties to Russia -- as too nebulous.
Beijing and Moscow have close ties which have strengthened since the Russian invasion of Ukraine.
On the battlefield, Zelensky said Kyiv had struck two weapons depots in southern and western Russia -- including a key site for Moscow's forces.
Russian authorities announced some evacuations and declared a local emergency.
Kyiv also said Russian attacks on Zelensky's hometown of Kryvyi Rig had killed a 12-year-old boy and two women in their 70s.
A 12-year-old girl and a woman in her 20s also died in a strike on the city of Nikopol.
Related Links
Learn about missile defense at SpaceWar.com
All about missiles at SpaceWar.com
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
