Members of DR Congo's opposition arrested in the southeastern city of Lubumbashi for allegedly insulting President Joseph Kabila were released on Wednesday, their party and police said.
"The militants who were arrested on Sunday and Monday have just been released," Dany Kabongo, an official for the main opposition Union for Democracy and Social Progress (UDPS), told AFP.
"We released all the people arrested during the visit to Lubumbashi by (opposition leader Felix (Tshisekedi)," regional chief commander Paulin Kyungu told AFP.
The releases followed diplomatic pressure in the form of a joint statement from EU officials and UN diplomats from the US, Swiss and Canadian missions to the country expressing concern at restrictions on opposition gatherings.
The statement called on the government to let gatherings by civil groups and the opposition proceed unhindered while urging such groups to ensure that their meetings were peaceful and respected the law.
Maman Sidikou, the UN's special representative and mission head for Democratic Republic of Congo, had on Monday condemned the detention of dozens of UDPS supporters dispersed with teargas and detained as they gathered at the airport to welcome Tshisekedi.
Tshisekedi then accused police of preventing him from leaving his hotel Tuesday to attend a party meeting.
Tensions are running high in DR Congo after Kabila failed to step down on the expiry of his second and final term last December.
Elections were due to take place this year under a transitional deal aimed at avoiding fresh political bloodshed in a country beset by ethnic divisions and fighting in its east.
But the country's electoral commission earlier this month announced there would be no vote before early 2019, sparking fresh security worries, while Tshisekedi has been urging a "transition without Kabila".
The international community has strongly urged a clear poll timetable be released. The United Nations has warned the current situation has created "tensions and a climate of uncertainty".