The Bahraini Interior Ministry said in a statement issued earlier that Salman was questioned about "violating certain aspects of the law", but did not go into any further details, RT reported.
The Al-Wefaq National Islamic Society said on Sunday that its leader was arrested after 10 hours of questioning by criminal police.
Salman was re-elected on Friday as leader of the opposition group.
His lawyer, Abdullah al-Shamlan, said that Salman had been accused of "inciting hatred against the regime and for calling for its overthrow by force".
Al-Wefaq said that the detention of its leader is "a dangerous adventure that will complicate the political situation in Bahrain".
In July, a Manama court suspended al-Wefaq’s activities so that it could correct its legal status, and later banned all of its activities in October. In November, the opposition movement said it was boycotting parliamentary elections.
Anti-government protesters have been holding peaceful demonstrations across Bahrain since mid-February 2011, calling for an end to the al-Khalifa dynasty.
Violence against the defenseless people escalated after a Saudi-led conglomerate of police, security and military forces from the Persian Gulf Cooperation Council (PGCC) member states – Saudi Arabia, Kuwait, the United Arab Emirates, Oman and Qatar – were dispatched to the tiny Persian Gulf kingdom on March 2011, to help Manama crack down on peaceful protestors.
So far, tens of protesters have been killed, hundreds have gone missing and thousands of others have been injured.
