The U.N. nuclear watchdog on Friday demanded an immediate reply from Iran on whether it would extend a monitoring agreement that expired overnight, prompting an Iranian envoy to respond that Tehran was under no obligation to provide an answer, Reuters reported.

The agreement continued the International Atomic Energy Agency's (IAEA) collection of data on some of Tehran's activities, cushioning the blow of Iran's decision in February to reduce cooperation with the agency.

"An immediate response from Iran is needed in this regard," the IAEA said in a statement summarizing a report by its chief Rafael Grossi to its 35-nation Board of Governors.

Grossi wrote to Iran last week "to understand Iran's position regarding the possible continued collection, recording and retention of data," the report said. As of Friday, Iran had not indicated if it intended to maintain the arrangement, it said.