The authorities in Iran have barred the Tehran-based correspondent for The New York Times from working for the past four months, the newspaper said Monday.

The correspondent, Thomas Erdbrink, a Netherlands citizen, has reported for The Times from Iran since 2012. He resides in Tehran but has been unable to work since late February, when his press credential was revoked.

The Times decided to make the issue public after recent speculation and comments on social media. Mr. Erdbrink’s absence from the news report has become increasingly conspicuous because of escalating tensions between the Iranian authorities and the United States.

Officials of Iran’s Foreign Ministry have repeatedly assured The Times that Mr. Erdbrink’s credential would soon be restored but have offered no explanation for the delays or for why it was revoked, said the Times international editor, Michael Slackman. He added that there are some indications this will be resolved soon.