Ukrainian President Volodymyr Zelenskiy has vowed to end Russia's occupation of the Crimea peninsula and all other areas in his country.
Russia seized and annexed Crimea in 2014 in a move not recognised by most other countries, and has occupied other parts of Ukraine since its full-scale invasion in February 2022.
Ukraine has begun a counteroffensive to try to regain the lost land.
"Crimea will be de-occupied like all other parts of Ukraine that are unfortunately still under the occupier," Zelenskiy told an international conference on Crimea in which he said representatives of more than 60 countries and international organisations were participating.
He said Ukrainian troops were moving ahead in a counteroffensive launched in early June, but gave no details.
He set no time frame for Ukraine to regain control of Crimea.
Russia shows no sign of abandoning Crimea, which it has used as a platform to launch missile strikes on Ukrainian targets.
Russia says a referendum held after its forces seized the peninsula showed Crimeans genuinely want to be part of Russia.
The referendum is not recognised by most countries.
Participants at the Crimea Platform conference heard speeches delivered by video by foreign leaders including Turkish President Tayyip Erdogan and French President Francois Macron.
Erdogan reiterated that Turkey does not recognise Russia's annexation of Crimea and supports Ukraine's territorial integrity.
He said Turkey was working hard to keep communication lines open in the hope that a "fair and durable" peace could be agreed.
Zelenskiy said that when Crimea was back under Ukrainian control, it would be part of Ukraine's economy and therefore part of the global economy.
"Today we are taking the first such economic step. We are signing the first document with companies that are ready to enter Crimea following Ukraine," he said.
He gave no details of the document but named several companies that he said were ready to invest in Crimea after the end of Russian control, including Ryanair, Vodafone, Nokia and EPAM.
Russia said on Wednesday it had thwarted the latest Ukrainian drone attack on Moscow but that three people were killed in a separate drone strike on a health facility near the Ukrainian border.
The governor of Russia's Belgorod region, which is near Ukraine and has come under frequent attack, said a drone had hit a sanatorium in a village, while another had been shot down.
He said two people had died on the spot and doctors were unable to save the life of a third person.
Separately, the governor of Kaluga region, south of Moscow, said another Ukrainian drone had been shot down without causing casualties or damage.
The attempted attack on Moscow was not reported to have hurt anyone and only appeared to have caused minor damage.
It was the latest in a surge of similar incidents, and once again forced Moscow's airports to briefly suspend flights as a precaution.
The Defence Ministry said air defence forces near the capital had shot down two drones over the Moscow region's Mozhaisky and Khimki districts.
It said a third had lost control but hit a high-rise building under construction in a Moscow business district.
Glass panes on three floors of the building were damaged, the state TASS news agency reported.
The same district, known as Moscow City, was hit twice in three days at the start of the month.
There was no immediate comment from Ukraine, which rarely takes direct responsibility for drone strikes on Russian territory or on areas controlled by Russia, but which appears to have stepped up such attacks since May.
Russia's state aviation authority said that all of Moscow's airports were later operating normally after a temporary flight suspension was imposed.
