The accusation was made on August 17 by Moldova's deputy foreign minister, Valentin Zubric, who said a high-ranking official at the Romanian Consulate in the Moldovan capital of Chisinau issued visas in exchange for bribes.
Basescu branded the claim an act of aggression. "It would be better [for Moldova] to stop provoking us," he said. "This is yet another orchestrated aggression, and this time our response will be extremely tough."
Basescu said Moldova's allegations are unfounded since the Romanian Consulate in Chisinau only has the authority to receive visa applications, which are then forwarded to Bucharest for approval.
Romanian Foreign Minister Adrian Cioroianu on August 17 also denied receiving an official complaint that Chisinau claims it sent in June.
Complications Of EU Membership
The dispute comes amid strained ties between the neighboring countries.
Romania introduced a visa regime for Moldovan citizens on 1 January, the date on which it joined the European Union.
Since then, huge lines have formed outside Romania's consulate in Chisinau. Romanian visas are free of charge for Moldovans.
Romania has also been struggling with a tide of applications for Romanian citizenship, which allows visa-free movement throughout the European Union. Currently, one in eight of Moldova's 4.3 million citizens has applied for a Romanian passport.
Basescu has promised to further ease the current legislation, which grants citizenship to Moldovans whose parents or grandparents were Romanian citizens before 1940, when Moldova was part of Romania.
Moldova accuses Bucharest of undermining its national security by encouraging Moldovans to become Romanian citizens.
Some 600,000 Moldovans currently live abroad. Moldova's GDP growth depends heavily on the spending of remittances emigrants send to relatives who remain in Moldova.
(RFE/RL's Romania-Moldova Service contributed to this report.)