The measure was taken amid pressure from the European Union, which is concerned about smuggling in and from the internationally unrecognized Transdniester region.
Yekhanurov told RFE/RL today that the decision is in accordance with international requirements.
"We have simply introduced international rules of the game and smuggling won't be tolerated any longer," he said. "And it looks like in recent days, after we introduced the international rules, there hasn't been any smuggling or so-called shadow economy on the border."
Yekhanurov also warned Transdniestrian separatists to respect Ukraine's borders.
Meanwhile, Moldovan officials said today that dozens of businesspeople from Transdniester were stopped by separatist authorities from crossing into Moldova.
The government had invited companies in Transdniester to attend a seminar in Chisinau about new customs requirements for exports to Ukraine.
(with material from AP, AP Flux)