By Anne Kauranen

HELSINKI, March 30 (Reuters) - A Ukrainian drone that crashed in Finland on Sunday carried an unexploded warhead according to a preliminary assessment, Finnish ‌police said on Monday.

Ukraine said it had apologised for the incident, and that the ‌drone fired in its war with Russia had gone astray, most likely because of electronic interference from Moscow.

There ​were no reported injuries or damage from the crash in Finland's southeast, the first time the Russia-Ukraine war has spilled onto its soil.

POLICE INVESTIGATING SECOND DRONE

Ukraine has stepped up drone attacks on Russian oil refineries and export routes over recent weeks, some close to Russia's border ‌with Finland, in an attempt ⁠to weaken Moscow's war economy.

"The UAV (Unmanned Aerial Vehicle) that came down north of Kouvola was found, in a preliminary assessment by the authorities, ⁠to have an unexploded warhead attached," Finnish police said in a statement.

It was identified as a Ukrainian AN-196 drone, with a wingspan of 6.7 metres (22 feet), and was destroyed in a controlled ​detonation.

Debris ​from a second drone, also thought to be ​Ukrainian, was found in the municipality ‌of Luumaki, east of the town of Kouvola, and officers were investigating whether it detonated when it crashed, police added.

"We can confirm that under no circumstances were any Ukrainian drones directed towards Finland ... We have already apologised to the Finnish side for this incident," Ukraine's foreign ministry spokesman said.

Finland's President Alexander Stubb and Ukrainian leader Volodymyr Zelenskiy discussed the ‌incident in a phone call on Monday.

"Alex and I ​see the situation in the same way. We ​are sharing all necessary information," Zelenskiy wrote ​on social media.

Some of Ukraine's allies sent Kyiv "signals" about the possibility ‌of scaling back its long-range strikes on ​Russia's oil sector amid ​a spike in global energy prices, Zelenskiy said on Monday.

Stubb did not ask Ukraine to reduce its strikes on Russian assets in Finland's vicinity in the call ​with Zelenskiy, Stubb's office ‌told Reuters. "This was not discussed between the presidents," it said in an emailed ​statement.

(Reporting by Anne Kauranen in Helsinki, Pavel Polityuk and Yuliia Dysa in Kyiv; ​Editing by Stine Jacobsen and Andrew Heavens)