Thai anti-government protesters have failed to stop candidates signing up for a general election, despite surrounding venues for registration.
Large crowds ringed a sports stadium in central Bangkok, in their latest attempt to thwart the February poll.
But some candidates managed to register instead at a local police station, which protesters then also besieged.
PM Yingluck Shinawatra called the poll after protests that demanded an unelected council take power.
The demonstrators believe political reform is needed before elections can take place.
On Sunday, tens of thousands took to the streets of Bangkok in a renewed protest.
The main opposition Democrat Party has said it will boycott the 2 February vote.
Hard-core protesters had camped out all night at the stadium in central Bangkok where candidate registration was due to take place.
Finding the entrances blocked, the political parties' delegations went to report their difficulties at the local police station - but then improvised, and carried out registration there, the BBC's Jonathan Head in Bangkok reports.
Protesters then moved in to surround the police station - but failed to stop the first stage of the parties' campaign being completed.
Officials from the ruling Pheu Thai party and eight others managed to register for the election by slipping into the stadium very early in the morning, while the protesters slept, the Associated Press reported, quoting the state Election Commission.
Registration is scheduled to continue for two weeks, and protesters have pledged to keep obstructing the campaign.
Our correspondent says there are also concerns about possible clashes between rival supporters, and about whether the result of an election which the main opposition party has chosen to boycott would be broadly accepted.
The military has suggested delaying the vote - but that would not change the underlying political loyalties which give a strong advantage to Yingluck Shinawatra's party.
Another victory by her side will not be accepted by those opposed to her family in the capital, and so will not end Thailand's turmoil, our correspondent says.
'Accept the system'
Ms Yingluck dissolved parliament and called an election on 9 December, after more than 150,000 demonstrators took to the streets calling for her government to step down.
On Sunday, Ms Yingluck said elections must take place and urged protesters to express their views at the ballot box.
"If we don't hold on to the democratic system, what should we hold on to?"
He Pheu Thai Party won the last election in 2011, and has a majority in parliament. However protesters say her brother - ousted former leader Thaksin Shinawatra - remains in charge.
Mr Thaksin is currently in self-imposed exile after he was overthrown in a military army coup in 2006 and convicted of corruption.