Polls have closed in Colombia's legislative elections that are seen as a referendum on peace talks with the Marxist group the Revolutionary Armed Forces of Colombia (FARC) and a trial run for a presidential vote in May.
Since they opened in late 2012 in Cuba, the talks that President Jose Manuel Santos has held with the fighters have dominated political life in Colombia.
In total, 102 Senate seats and 168 seats in the lower chamber were up for grabs on Sunday in the country of 47 million.
Santos is seeking a second term, and his three party coalition government is expected to retain control of both chambers of Congress.
That would be key for the peace process, which so far enjoys the support of most Colombians, the AFP news agency reports.
"I am calling for all Colombians to vote and for these elections to be peaceful, to be normal, for everyone to vote for whom they want and then to accept the results as in any democratic system like ours," said Santos after voting.
Alvaro Uribe, Santos' predecessor and the most outspoken critic of the peace talks, is expected to easily win the Senate seat he is seeking.
If Uribe and others from his Centro Democratico party are able to gain seats in both houses they could try to dilute the president's vision for peace, though they are not expected to gain enough seats to undo majorities Santos currently holds in both chambers.
Uribe has strongly criticised part of the possible peace deal which would allow members of the FARC to eventually run for political office without having served jail time, the Reuters news agency reports.
"I fear what will happen if they [government] sign this impunity pact with the heads of terrorism," Uribe said at a recent campaign event.
"The lack of justice impedes forgiveness, the lack of justice gives a bad example to get involved with drug trafficking.
"And many youth will leave university and school to find easy money in drug trafficking.
"The lack of justice gives a bad example when the criminal is champion and there are no conditions placed in the pardon of a criminal.
"The lack of justice could mean that there are peace accords in Havana and more violence in Colombia."
'Mandate of the people'
FARC, considered a terrorist organisation by the US and the European Union, largely finances itself with the illegal narcotics trade and has fought a five-decade insurgency that has killed more than 200,000 people.
However, Congressman Juan Manuel Galan who is running for re-election on the Liberal Party ticket which generally supports Santos, said the next Congress should secure a peace deal to end the decades of bloodshed.
"But this election is different, it's distinct. This is the most important election of the republic's Congress in the last 50 years in our country because it's a Congress that will not only get from the mandate of the people but also the peace mandate," Galan said.
Santos is expected to win re-election in May, but political analyst Alejo Vargas told Reuters the congressional elections could reshape the government.
"For President Santos and his government it's very important to know exactly which parliamentary forces he will have in his second term, what will be the correlation and what is the weight of each senate member because that will have an impact on the formation of the new government, but also in the short term also to see the support that President Santos' candidature will receive upon re-election," Vargas said.