Limited internet access briefly returned in Iran before dropping again, a monitor said Sunday, 10 days into a communications blackout that rights groups said aimed to mask a protest crackdown that killed thousands.

Iran's president warned that an attack on the country's supreme leader would be a declaration of war -- an apparent response to US counterpart Donald Trump saying it was time to look for new leadership in Iran.

Demonstrations sparked in late December by anger over economic hardship exploded into protests widely seen as the biggest challenge to the Iranian leadership in years.

The rallies subsided after the crackdown that rights groups have called a "massacre" carried out by security forces under the cover of a communications blackout that started on January 8.

Monitor Netblocks said late Sunday that "traffic levels have fallen after a brief, heavily filtered restoration of select Google and messaging services in Iran".

Iranian officials have said the demonstrations were peaceful before turning into "riots" and blamed foreign influence from Iran's arch-foes the United States and Israel.

Trump, who joined Israel's 12-day war against Iran in June, had repeatedly threatened new military action against........

© Al Monitor