The orders given by the Rwandan general were clear and stirring. "Now the time has come when you must fight for your country," he told a gathering of soldiers at the national military academy.
But this new campaign would not be waged on Rwanda's territory. Instead, this specially formed battalion of the Rwandan Defence Forces was about to be dispatched over the north-western frontier and into the Democratic Republic of Congo, where it would inflame one of the world's bloodiest civil wars by fighting alongside a brutal rebel movement, led by an indicted war criminal.
A former NCO with this Rwandan unit has given The Daily Telegraph a detailed account of how he fought in support of M23 insurgents in eastern Congo between July and September, joining assaults on two towns and a border crossing.
Another Rwandan separately told how he was detained by his country's army in June and sent to Congo, where he served as a battlefield porter. He was based in a military camp run jointly by M23 rebels and Rwanda's army.
Together, their accounts contradict Rwanda's repeated denials of any role in Congo's conflict. They provide independent confirmation of a United Nations report that has accused Rwanda of helping M23's campaign.
They will also raise questions over why Britain is the only European country still giving aid directly to President Paul Kagame's government in Rwanda.
By sending troops to fight alongside M23, Rwanda stands accused by critics of escalating a devastating war and helping to force at least 500,000 civilians from their homes. It would also have broken UN Resolution 1897, which bans any country from giving military "assistance, advice or training" to any group in Congo.
By helping M23, Rwanda will also have chosen to ally with Bosco Ntaganda, the rebel movement's titular leader, who has been indicted for alleged war crimes. Furthermore, M23 defied the unanimous will of the UN Security Council and seized the city of Goma on Tuesday.
This assault on the biggest urban centre in eastern Congo claimed yet more lives, forced thousands to flee and inflamed the war still further.
Britain remains Rwanda's largest bilateral aid donor, promising the country pounds 75 million this year. Unusually, pounds 37 million of this money will go straight into Mr Kagame's government coffers as "budgetary support".
Andrew Mitchell, the former international development secretary, delayed a payment of pounds 16 million in July when the UN published its first findings about Rwanda's role in Congo. But he announced the release of this money on his last day in office in September. Justine Greening, who replaced him in a Government reshuffle, will decide next month whether to hand over the remaining pounds 21 million of British money.
All British aid is reserved for education, health, agriculture and development - there is no question of any funds being used for military purposes. Yet by subsidising Rwanda's government, Britain risks giving Kagame more discretion. He could rely on outside donors, who provide 46% of his national budget, to fund essential services and use his own resources in other ways.
Jean-Paul Nsengiyumva (not his real name) served as an NCO with a regular Rwandan infantry battalion until June, when he was transferred to a "special battalion" created to fight in Congo. After being briefed by one of Rwanda's most senior generals at Gako Military Academy, his unit was sent to back up Congo's rebels.
"At that time, M23 did not have many soldiers, so when the fighting was hard, they were calling us for help. Then we would come over the border and take the town," he said. "When we finished, we would pull back to Rwanda and allow M23 to occupy the area." Three times, his unit went over the frontier and into battle at M23's request, helping to seize the border crossing at Bunagana and two other towns. In September, however, Nsengiyumva's unit was deployed to bolster an M23 assault on a big Congolese army camp. This battle was tougher than expected - two attacks were beaten off and Rwandan forces with their rebel allies only succeeded at their third attempt.
Nsengiyumva, tired and sickened by months of fighting, chose to desert in the confusion that followed. He surrendered to Congo's army and was jailed in Goma until being released during the chaos that preceded its capture this week.
A younger Rwandan with no military experience also found himself drawn into Congo's war. Nsengimana Ngaruye (not his real name) was detained by Rwandan soldiers inside his home country while returning home from a village market in June.
He and three friends were ordered to join a group of soldiers and carry their packs and ammunition. He was then taken to a military base and, in return for payment in food, told to carry the baggage of Rwandan soldiers into Congolese territory.
For more than two months, Ngaruye, 24, was based at a military camp inside Congo called Mbuzi. He was taught how to fire a Kalashnikov assault rifle and given a steady diet of indoctrination by Rwandan officers and Congolese rebels.
"They used to tell us, 'Your enemy is the government of Congo, we need you to fight them and once we take over the country, you will get rewarded'." Ngaruye said the camp was filled with Rwandan soldiers and Congolese rebels, although a colonel in the Rwandan army was in command. He never fought, but carried ammunition and supplies whenever an attack was launched. In September, he deserted. He surrendered to the Congolese army and was also jailed in Goma until being freed last week.
Congo's government accuses Rwanda of wanting to dominate the east in order to loot its mineral wealth. But the armed group responsible for the genocide of Rwanda's Tutsi minority in 1994 remains at large in Congo's rainforest, giving Mr Kagami genuine cause to fear for the security of his frontier.
Mr Kagame says that "not one bullet" has passed from Rwanda into Congo. The British Government will decide by December 15 whether to give him the next tranche of aid.