by Jim Muir (BBC).
Syria has denied being responsible for two car bombs which killed 46 people in a Turkish border town.
Information Minister Omran al-Zoubi told a news conference on Sunday his country “did not commit and would never commit such an act because our values would not allow that”.
Turkish police say that nine people have been arrested in connection with Saturday’s attacks in Reyhanli.
Ankara has said that it suspects the involvement of Syrian intelligence.
The Turkish government said on Sunday that the number of people killed in the blasts had risen to 46 and that more than 50 others were still being treated in hospital.
All nine of those arrested in connection with the attacks were Turkish citizens, officials said.
“This incident was carried out by an organisation which is in close contact to pro-regime groups in Syria and I say this very clearly, with the Syrian Mukhabarat,” Interior Minister Muammer Guler told Turkish TV.
Turkey, a Nato member, is a strong supporter of the opposition in Syria’s civil war and a vocal critic of President Bashar al-Assad’s government.
The US and Nato have condemned the bombings and expressed support for Turkey.
Hundreds of mourners have been attending the funerals of the victims in Reyhanli, which is home to many Syrian refugees.
Mr Zoubi said that “it is not anyone’s right to hurl unfounded accusations”.
“We were saddened by the martyrs’ deaths” [on] Saturday in the town of Reyhanli,” he said.
“It is [Turkish Prime Minister Recep Tayyip] Erdogan who should be asked about this act. He and his party bear direct responsibility.”
Mr Zoubi also launched what correspondents say was one of the harshest personal attacks on Turkey’s prime minister by an Syrian official so far. He demanded that Mr Erdogan “step down as a killer and as a butcher”.
The BBC’s Jim Muir in Beirut says that it was a robust response from Damascus, throwing responsibility for the blasts firmly back on the Turkish authorities.
Mr Zoubi said it was the Turkish government that had facilitated the flow of arms, explosives, vehicles, fighters and money across the border into Syria.
He said that this had turned the border areas into centres for international terrorism and the Turkish leadership had to take political and moral responsibility for it.
Turkish Foreign Minister Ahmet Davutoglu has vowed to catch those behind the attack. On Sunday he said that he believed fighters loyal to Syrian President Assad were responsible.
The Syrian opposition coalition has added its voice to the Turkish accusations that Damascus was behind the bombings, saying it was a blatant attempt to drive a wedge between Turkey and the thousands of Syrian refugees who have been given shelter on the Turkish side of the border.
Mr Davutoglu said that the attacks “have nothing to do with the Syrian refugees in Turkey, it’s got everything to do with the Syrian regime”.
He said that it was “not a coincidence” that the bombings occurred as diplomatic efforts to solve the Syrian crisis were intensifying.
“There may be those who want to sabotage Turkey’s peace, but we will not allow that,” he said.
“No-one should attempt to test Turkey’s power. Our security forces will take all necessary measures.”
He said those behind Saturday’s bombings were believed also to have been behind an attack on the Syrian coastal town of Banias a week ago, in which fighters backing President Assad in the civil war were reported to have killed at least 62 people.
Pressure on Turkey
Reyhanli is an entry point for refugees fleeing violence in Syria and local people attacked Syrian refugees and cars with Syrian number plates after the attack, according to local media.
The Turkish government said the bombings were intended to pit Turks against Syrian refugees in Reyhanli, adding that refugees had no role in the attack.
BBC World Affairs correspondent James Reynolds says the attacks will put pressure on the Turkish prime minister.
Mr Erdogan’s policy on Syria has always been to support the Syrian opposition but not become involved in the war, but the attacks now make it very difficult for him to carry on staying out of the conflict, our correspondent says.
He is scheduled to meet President Barack Obama in Washington on Thursday with the US currently considering its options over Syria.
There has been some speculation that the bomb attacks may strengthen the hand of those urging the creation of a no-fly zone and safe haven for the Syrian opposition inside Syrian territory.