Turkey vowed a strong response and Syria branded Turkey's prime minister "a butcher."
bombings
Harsh accusations from both sides signaled escalation of tensions between two former allies
Among the nine people detained overnight was the alleged mastermind of the attack
Saturday's bombings left 46 people dead in the Turkish border town of Reyhanli
Nine Turkish citizens believed to have links to the Syrian intelligence agency have been detained in connection with twin car bombings that shattered a Turkish border town, officials said Sunday, as Syria rejected allegations it was behind one of the deadliest attacks in Turkey in years.
More:Turkey: 9 with Syrian ties arrested in car bombings