Chinese online search engine Baidu.com went down today in an episode some users suspect has to do with Iranian Internet hackers.

According to reports in Chinese local media, starting from 07:00 this morning, the Chinese search engine Baidu.com experienced a massive failure and users in many cities and provinces in China said they were unable to visit the website.

In response to this problem, the search engine provider has published an official announcement, stating that the reason for users’ failure to access Baidu.com is attributed to illegal domain name tampering by its domain name registrar in the United States. The company is apparently currently handling this problem and users who cannot visit Baidu.com can use Baidu.com.cn instead to open the website.

Public files show that Baidu’s domain name registrar is Register.com and Baidu’s domain name server reportedly was also modified to that of Yahoo at one point. Chinese Internet users from Beijing, Liaoning, Jiangsu, Sichuan, Anhui, Guangdong, and Wuhan told local media that they were unable to open the website of Baidu or the website jumped to Yahoo’s English website when they were trying to open Baidu’s search engine.

However, other media, including some foreign media like The Wall Street Journal, report that Baidu.com may have been attacked by Iranian hackers, because some users today saw a banner for the “Iranian Cyber Army” when they tried to access Baidu’s homepage.

So far, access to Baidu.com has recovered in some areas and the company said the exact time for a complete recovery is unpredictable.