A deft piece of Franco-Saudi diplomacy has yielded a $3bn grant from Riyadh to fund purchases of military equipment for the Lebanese army, in a bid to bolster security in the country.

Lebanon’s president Michel Sleiman announced in a TV address on 29 December that the kingdom had pledged $3bn for the Lebanese army to buy French arms equipment – the largest ever grant to the nation’s military. The announcement came the same day as a meeting in Riyadh between King Abdullah bin Abdulaziz al-Saud and the visiting French president, Francois Hollande.

In recent months, the Lebanese Armed Forces (LAF) have struggled to quell rising violence, and the outbreak of bombings on the streets of capital Beirut has triggered calls for the military to do more to assert its authority. The promised Saudi funding – similar to financial pledges Riyadh has made in the past year to Egypt – is viewed as a means of strengthening the army’s capabilities, in the face of a considerably more powerful domestic militia, Hezbollah.

The timing of the announcement, just two days after the assassination of the prominent Sunni politician Mohamad Chatah, suggests renewed impetus among the Saudi hierarchy to match its political support to the Lebanese opposition with hard cash. And with the increasingly close ties developing between France and Saudi Arabia – in contrast to the frosty atmosphere that has enveloped Saudi-US relations – there is now a viable conduit to match the funding to French defence equipment sales.

During his visit to the kingdom, Hollande said his country would meet any demands for weapons from Lebanon. “I am in touch with President Sleiman… If demands are made to us, we will meet them,” he said.

France – the former colonial power – and Saudi Arabia share a common interest in Lebanon, as staunch supporters of the Sunni-Christian-Druze backed March 14 coalition. They are also both fierce opponents of the Hezbollah-Syria-Iran axis. Hezbollah has accused Saudi intelligence of involvement in the 19 November bombing of the Iranian embassy in Beirut.

The funding is sorely needed by the LAF. Numbering less than 60,000 troops, the army remains a non-sectarian institution that enjoys broad support from all Lebanon’s communities. However, its effectiveness has been blunted by budgetary constraints, and it is in particular need of armoured vehicles and counter-insurgency equipment.

A five-year LAF procurement plan worth $1bn was authorised in 2012, but the Lebanese state has insufficient funds to pay for it. And while the US provided $400m in military aid between 2005 and 2008, Congress has been susceptible to pressure from Israel to halt funding to the LAF, in case weaponry ends up in the hands of Hezbollah.

Now the LAF has the promise of hard cash to build up its capacity. But the decision to accept the Saudi funding also raises the political stakes considerably; Hezbollah will view the $3bn grant as a direct challenge to its authority, coming as it does from a noted enemy such as Riyadh.

President Sleiman’s hearty welcome for the funding represents another shift in the political weather in Beirut, allying the presidency – traditionally viewed as politically neutral – more clearly with the Western-Sunni consensus.

Sleiman’s big challenge, as he sees out the last months of his term in office, will be to ensure Lebanon does not pay too high a political price for the much-needed military aid.