Belgium summoned the Russian ambassador to Brussels on Wednesday in a spat over Moscow's claim that Belgian jets killed six civilians near Syria's Aleppo.
The diplomatic summons was issued after Russia said two Belgian F-16s from the US-led coalition had been identified in the region where the deadly air strike took place Tuesday.
"We are making contact with the Russian ambassador with the aim of summoning him today," Belgian foreign ministry spokesman Didier Vanderhasselt told AFP.
"We are also making contact at the level of the ministry of defence to pass on the message that Belgium has no responsibility for these air strikes... We are also unhappy that this information was not verified before being made public."
Russia's defence ministry said two of Belgium's F-16s fighting Islamic State militants in Syria had been identified in the area where the deadly strike took place.
"Six people were killed and four people injured to various degrees as a result of bombing that destroyed two homes" in the village of Hassajik in the Aleppo region, it said in a statement.
Belgian defence ministry spokeswoman Laurence Mortier earlier denied the country's air force was active in the area at the time.
But responding to the Belgian summons, Russian defence minister spokesman Igor Konashenkov said Moscow was confident of its information.
"Russia has effective air defence capabilities, allowing it to carry out 24-hour monitoring of air activity practically over the whole territory of Syria and beyond its limits," he said.
"We would like to remind you that for the countries of the international coalition that Belgium is part of, such errors in designating targets are not at all something impossible and unfortunately are happening regularly," he added.
Moscow had announced on Tuesday that the Russian and Syrian air forces had stopped bombing Aleppo to pave the way for an eight-hour truce on Thursday.
Russia said Wednesday it was extending the eight-hour truce in Aleppo to 11 hours to allow civilians and rebels to leave the city's rebel-held east.
The extra time will allow representatives of the United Nations and the Syrian Red Crescent to evacuate the sick and wounded, "and also to allow peaceful civilians out of the city", a defence ministry spokesman said.
Russia also said its planes and Syria regime jets were keeping 10 km away from Aleppo.
The government offensive against rebel-held eastern Aleppo -- which has destroyed hospitals and other civilian infrastructure -- has plunged Syria into some of the worst violence of the five-year war that has claimed over 300,000 lives.
The West has accused Russia of potential war crimes over its bombing campaign in Aleppo in support of the regime offensive.
The US State Department voiced scepticism regarding Moscow's planned truce while welcoming a halt in the bombardments.
President Vladimir Putin is set to face Western pressure over the conflicts in Syria and Ukraine at international talks in Berlin on Wednesday as Russia comes under increasing criticism over its support for Damascus.