KHARTOUM, May 15 (Reuters) - Sudan accused Chad of sending warplanes into its territory twice on Friday, stoking growing tensions between the neighbouring countries.

The accusation comes a week after Chad said Sudan sent rebel forces over its border, raising fears that a recent peace deal could collapse. Both countries have regularly accused each other of backing insurgents bent on overthrowing their respective governments.

"Three warplanes have crossed the borders to an area south of El Geneina (capital of Sudan's West Darfur state) which is 60 kilometres inside Sudanese territory," said Ali Youssef Ahmed, head of protocol at Sudan's Foreign Ministry.

"It happened at 10.30am and 1.30pm.... It is a violation of our territorial sovereignty. Sudan is in a position to defend its territory," Ahmed told Reuters, but declined to say whether Sudan planned to retaliate. "We are considering all options".

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