BANGKOK - Police in Thailand raided the office of an independent news website on Tuesday to look for leaflets urging a vote against a draft constitution proposed by the country's military government. They left empty-handed without making any arrests.

The raid on the Prachatai website's office in Bangkok was carried out under a search warrant that related it to the arrest two days earlier of one of the website's reporters. Taweesak Kerdpoka had been arrested because he got a ride with three political activists in a vehicle carrying copies of such leaflets. He had been covering their activities in the western province of Ratchaburi.

Prachatai director Chiranuch Premchaiporn said five plainclothes police officers carried out Tuesday's office search, while more than 10 military personnel were stationed outside. Police signed a document acknowledging that they found no material they were seeking, she said.

Prachatai often carries stories critical of the government, but the raid seemed more directed at demonstrating the limit of official tolerance for criticism of the charter. Lobbying against the charter is generally prohibited.

The Referendum Act, applicable to the upcoming Aug. 7 vote on the draft charter, calls for a prison term of up to 10 years for anyone who publishes or distributes content about the draft constitution that is deemed to be deviating from the facts, contains rude and violent language, or threateningly discourages voters from participating in the referendum. In practice, it is applied to discourage opponents of the draft.

The army ousted an elected government in May 2014 and has enacted broad measure limiting freedom of expression. The junta has promised to hold an election next year after two postponements. It has not clearly spelled out what will happen if voters reject the draft constitution, which critics call undemocratic.

Chiranuch said the police indicated they suspected the "Vote No" material they confiscated on Sunday was produced at the Prachatai office.

"We have nothing to hide here except for a messy office, so I allowed them to enter after having them identify themselves," she said.

The three activists of the New Democracy Movement and the Prachatai reporter who was with them were freed on bail on Monday.

"Arresting peaceful activists is bad enough, but jailing a journalist for reporting on the 'vote-no' campaign is a serious blow to press freedom in Thailand and any hopes that the vote on the constitution will be a fair one," Brad Adams, Asia director at Human Rights Watch, said in a news release. "With each day the Thai junta is undermining the legitimacy of its own referendum."

News from © The Associated Press, 2016