"This is a blow, it's a step backwards," Serbian Foreign Minister Vuk Jeremic told B92 television in Belgrade.
He said his counterparts in the three neighboring states had told him they had been under heavy pressure to recognize Kosovo and had expressed hope they could keep good relations, Reuters reported.
"But we can't, unfortunately. If we didn't react in a diplomatic way, we wouldn't be taken seriously as a sovereign state," Jeremic said.
He did not say what sort of "pressure" his counterparts were referring to. Kosovo's independence is backed by the major NATO and European Union governments. Bulgaria and Hungary are NATO and EU members and Croatia aspires to join both blocs. Their action dealt a blow to Serbia's campaign to overturn Kosovo's month-old independence.
"Following official notification the Foreign Ministry has given orders to the ambassadors in Croatia and Hungary to leave their posts," said ministry spokeswoman Vesna Sekerezovic.
"The ambassadors have 48 hours to return to Serbia."
She said the embassy in Sofia was expecting Bulgarian authorities to send official notification on the recognition of Kosovo, which was announced later in the day.
"Once they do that, the ambassador in Sofia will be told to leave," she said.
There was no evidence of strong public reaction in Belgrade to the action by the neighboring states. Their embassies have not been targeted by protesters.
But some Bulgarian truck drivers complained Serbs had hurled stones at their trucks while crossing the country on Wednesday, Bulgarian media reported. Travel agencies also said Serb border police had turned hostile in the last few days.
Bulgaria's main export route to Europe goes via Serbia and companies say they may lose millions if they have to bypass the country.
Bulgarian Prime Minister Sergei Stanishev told a news conference he was aware of the risks facing Bulgarian investors in Serbia but did not expect a major economic backlash.
"We are taking all the necessary and possible measures to guarantee Bulgarian interests, including those of cargo companies and Bulgarians traveling through Serbia," he said.