UNITED NATIONS -- Inspectors from the International Atomic Energy Agency (IAEA) are on their way to visit two facilities in Ukraine after Russia's "dirty bombs" allegations, chief of the UN nuclear watchdog said here Thursday.

"Allegations have been made, inspections are on the way," IAEA Director-General Rafael Grossi told reporters at the UN headquarters after attending a closed-door Security Council meeting.

Inspectors are expected to go to the two locations "in a couple of days" and could reach a conclusion in days, Grossi said.

A separate press release from the IAEA said its inspectors this week would carry out verification activities at two locations in Ukraine, following a written request from the Ukraine government to send teams of inspectors there.

Ukraine's request was issued after Russia made allegations about activities related to the possible production of "dirty bombs" at the two locations, which are under IAEA safeguards and have been visited regularly by IAEA inspectors, the agency said.

The purpose of this week's safeguards visits is to detect any possible undeclared nuclear activities and materials related to the development of "dirty bombs," the IAEA said, adding that it inspected one of the two locations a month ago and no undeclared nuclear activities or materials were found there.