BANGUI (Reuters) - Rwanda and Russia have sent troops and supplies to the Central African Republic to help counter a surge in violence by rebel groups ahead of Sunday’s election, officials and a security source in Bangui said. Security forces and U.N. peacekeepers have been battling rebels who have occupied towns and roads outside the capital. The authorities accuse former president Francois Bozize, whose presidential candidacy was rejected by the courts, of plotting a coup with several militant groups. A spokesman for Bozize’s KNK party has denied the accusations. The United Nations Security Council condemned the violence by armed groups and other militia in a statement on Monday after being briefed on the situation by U.N. peacekeeping chief Jean-Pierre Lacroix. “The members of the Security Council called on all actors to urgently cease hostile actions and work towards ensuring conditions conducive to the holding of the upcoming elections,” the council said. President Faustin-Archange Touadera, who is seeking re-election, came to office in 2016 after Bozize was overthrown in a rebellion three years earlier. He has struggled to restore stability and swathes of the country remain beyond government control. The CAR government said on Sunday that Rwanda and Russia “took steps to provide effective support which arrived on Central African territory today”. The Rwandan Defence Ministry confirmed it had sent troops. Russia, which has previously sent arms and military contractors to CAR as it seeks to increase its influence in Africa, denied media reports it had sent in troops and military aid. “Apart from five employees of Russian defence ministry’s mission at the CAR’s defence ministry, there are no other Russian military personnel (in the country),” Russia’s ambassador to CAR, Vladimir Titorenko, was quoted as saying by Russia’s state RIA news agency. “But instructors who teach the CAR’s army upon its government’s request do work here. Periodically there is a rotation of them, and this is well known to the U.N. Security Council and the world community,” Titorenko said. But a security source in Bangui said over the past few days, Russian planes have landed carrying military personnel and supplies. On Monday, presidential spokesman Dmitry Peskov said Russia considered the situation in CAR “a matter of serious concern”. Touadera has friendly ties with Moscow and has a Russian national as a security adviser. U.N. peacekeeping mission MINUSCA said on Monday there had been a “slight lull” near the town of Yaloke following an attack over the weekend by armed groups. A security and humanitarian source also said the town of Mbaiki, about 100 km (60 miles) from Bangui was calmer following clashes. The United States, France and Russia have also accused Bozize of seeking to disrupt the election.