Ugandan President Yoweri Museveni is set to meet his Rwandan counterpart Paul Kagame on Friday at the central African countries' shared border in a bid to resolve a continuing dispute between the two leaders.

For years, the two leaders were by each other's side and supported one another to climb the ladder of power in their respective countries.

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In 1986, Kagame was part of the rebel fighters led by Ugandan President Museveni that took power in Kampala.

Almost a decade later, Museveni returned the favour by arming and supporting Rwandan rebels led by young Kagame to seize power in Kigali.

The two longtime allies even teamed up again in 1996 to bring down the flamboyant Mobutu Sese Seko, one of the continent's longest-serving leaders and installed Laurent Kabila as president in the neighbouring Democratic Republic of the Congo (DRC).

But more recently, relations between the two leaders has been, at best, frosty.

Kagame, 62, accuses his former ally of backing rebel groups and dissidents who want to bring down the government in Kigali.

Speaking at a news conference last March, then-Rwandan Minister of Foreign Affairs Richard Sezibera accused Kampala of supporting the Rwanda National Congress (RNC) and the Democratic Forces for the Liberation of Rwanda (FDLR). Rwanda considers both groups to be "terrorist organisations".

"Groups which have carried out acts of terrorism inside Rwanda, they carried out grenade attack in Kigali, they have carried out attacks in the north of our country, they have carried out attacks in the south of our country, the leaders of those groups carrying out the activities [are] in Uganda seemingly freely with the support of some officials of the government of Uganda," Sezibera said.

A month later during a speech to mark 25th anniversary of Rwanda's genocide, a visibly angry Kagame warned Uganda against interfering in his country's internal affairs.

"Those who think we have not seen enough of a mess, and want to mess with us, whether from here or from outside, I want to say: We will mess up with them big time," said Kagame, who has accused Uganda of sponsoring attacks in his country.

"We are going to raise the cost on the part of anybody who wants to destabilise our security," Kagame said in November.

Kigali has also accused Kampala of targeting its nationals, with the government advising Rwandans to avoid Uganda.

Museveni has denied that his country supports the rebel groups and has instead accused Kigali of trying to violate its sovereignty.

It is "wrong" for "Rwanda agents to try to operate behind the Government of Uganda," Museveni, 75, said in the letter he sent to Kagame in March last year.

Uganda claimed that Rwandan soldiers entered its territory in the southwest district of Rukiga and shot and killed two suspected smugglers last May.

Uganda's foreign ministry condemned "the criminal, brutal and violent act by the Rwandan soldiers" against its civilians.

Kampala has also accused its tiny landlocked neighbour of supporting the Allied Democratic Forces (ADF) rebel group, which has been blamed for a number of attacks in Uganda and eastern DRC that has left hundreds of people dead. Rwanda denies the charges.

Regional trade affected

The long-simmering feud snarled regional trade in February when Rwanda closed its busiest road crossing - known as Katuna to Ugandans and Gatuna to Rwandans - to Ugandan cargo trucks. Rwanda briefly opened the crossing in June before closing it again.

"On the Rwandan side, it is the ordinary citizens feeling the dispute between the two countries. Prices of basic good have increased considerably. On the Ugandan side, it is companies, for example cement manufacturers, that are feeling it the most," Goloba Mutebi, a Kampala-based researcher, told Al Jazeera.

"Tanzania is the only winner here because the goods that Rwanda used to import from Uganda is now imported from there," he added.

Nothing to worry

There is fear that the dispute between the two leaders, with their sizeable military forces and spy network, could plunge the region into a fresh crisis. But observers say the dispute is nothing new.

"For more than a decade Museveni and Kagame have not seen eye-to-eye. Kagame feels Museveni behaves as if Rwanda is not a sovereign country, that Rwanda is a province of Uganda. On the other hand, Museveni thinks Kagame is not grateful to him, that Kagame has forgotten who got him where he is today," Yusuf Serunkuma, a Kampala-based political analyst, told Al Jazeera.

Analysts in the region say it is in the interest of the two leaders, the longest-serving in their region, to resolve the dispute.

"Museveni has an election coming up next year. The last thing he will want is the border closure to become a campaign issue," Serunkuma said.

"For Kagame, Rwanda will not be able to afford importing goods from Tanzania for long. It costs a lot more and Rwanda's small economy and government cannot continue to bear the burden," Serunkuma added.

As the two leaders meet in Katuna on Friday, traders and those living in the border area will hope the border crossing will be reopened - for good this time.