Bahraini human rights campaigner Nabeel Rajab has been granted an official pardon from King Hamad bin Isa Al Khalifa after serving three months of his six-month jail term.
The king was prompted to act because of fears over Rajab's health, reported the BBC.
Rajab was taken into custody in April and charged with insulting public institutions on Twitter.
In May, an appeals court had upheld the six-month prison sentence he had received.
The activist is a member of the island's Shia majority and has served several jail terms since setting up the Bahrain Centre for Human Rights in 2002.