Russia's Vladimir Putin has arrived in Serbia at the head of a powerful delegation, aiming to cement ties with a country seeking to join the EU.
As well as a red-carpet welcome, President Aleksandar Vucic gave him a puppy while Mr Putin awarded his counterpart a Russian state honour.
Some 7,000 police have been deployed for the brief visit, and crowds have gathered in Belgrade ahead of a parade.
Mr Vucic said 30,000 people have already turned out to greet Mr Putin.
The parade is set to take place on Thursday evening when the Russian leader visits the Church of St Sava, the biggest Orthodox church in Serbia.
What has Putin said?
Ahead of his visit, Mr Putin accused the US and other Western countries of "destabilising" the Balkans.
He said they had tried to secure dominance in the Balkans, by absorbing Montenegro into Nato and seeking to bring Macedonia into the Western military alliance too.
Although Serbia is a candidate to join the European Union, it remains a close ally of Moscow. Some 21 deals are set to be signed between the two sides, including on energy and defence.
Before the visit President Putin also promised to continue developing military and technical co-operation with Serbia and criticised the EU's handling of Kosovo.
And finally the puppy pic we've been waiting for: Putin is given a shepherd dog as part of his Slavic brotherhood tour of Serbia. Its name is Pasha (rather than, say, Donald). @dimsmirnov175 pic.twitter.com/65eENA2LCc— Alec Luhn (@ASLuhn) January 17, 2019
The Serbian leader praised the two countries' increasing partnership and said he believed they could improve trade too.
The tight security measures in Belgrade followed big opposition protests against President Aleksandar Vucic and his ruling SNS party over recent weeks, with demonstrators accusing him of clamping down on media freedom and attacking the opposition.
Residents had earlier been urged not to go on their balconies to watch Mr Putin being driven through Belgrade.
What are Putin and Serbia up to?
By Guy Delauney, BBC Balkans correspondent
It is a question that just will not go away: if Serbia is so determined to join the European Union, then why does it keep making such a show of its friendship with Russia?
Playing up ties with Moscow appeals to the conservative-nationalist core support of President Vucic and his Progressive Party. It emphasises the Slavic, Orthodox Christian character of the country even as Serbia's direction of travel is westward.
It also helps Mr Vucic to argue that policies which bring Serbia closer to EU membership - such as normalising relations with Kosovo - are not imposed by Brussels, but rational choices to improve the lives of the country's people.
Diplomatically, playing host to Russia's president is a reminder to the EU not to take Serbia's loyalty for granted - and to stick to its accession target of 2025.
Meanwhile, Vladimir Putin will doubtless enjoy the discomfort of Western diplomats observing the prime candidate for EU membership rolling out the red carpet for him.