The accusation came a day after security forces were reported by Syrian media and officials to have fought Muslim fighters near the defence ministry in a gun battle that left four insurgents and a police officer dead.
Six insurgents, including two who were wounded, were captured and two policemen were also injured.
"What happened in the heart of Damascus is a practical translation of the American-Israeli threats. Targeting Syria is still an official policy of the US administration, the Tel Aviv leaders and some weak-willed people who have sold themselves for evil in exchange of a handful of dollars," state-run Tishrin daily said in an editorial on Saturday.
The US blames Syria for backing Muslim groups such as the Palestinian Hamas and Islamic Jihad, as well as Lebanon's Hezbollah. America also accused Syria of allowing foreign fighters to cross into Iraq, an accusation the Arab state denies.
Syria's official news agency, Sana, said all 10 insurgents in Friday's attack were members of a takfiri group. Takfiri refers to Sunni Muslim extremists who declare that non-radical Muslims are infidels.
On Friday, the fighters were reportedly first spotted in a building in Ummayad Square, central Damascus, by a police patrol, which then opened fire.
Fayez al-Sayegh, director-general of Syria's state-run radio and television services, said the clashes erupted at 6am (0300 GMT) when a "group of extremists" tried to storm deserted buildings near the country's state-run radio and television complex.
Officially released photo shows
the slain fighters and weapons
Initial reports suggested that the media building itself was being attacked.
However, Emad Fawzi al-Shaaibi of Syria's Strategic Research Centre told Aljazeera that it seemed the attackers wanted to use the deserted buildings near the media centre as a base to attack other buildings nearby.
Ummayad Square houses several state buildings, hotels and security installations.
On Saturday, Sana said police seized 10 US-made automatic rifles, along with several homemade bombs. It did not specify the weapons' brand, but said they had been supplied by a "neighbouring country to carry out sabotage attacks against vital targets and national interests".
The country was not named, but Syria has alleged in the past that weapons were coming into the country from Lebanon, with whom relations have been increasingly strained since the assassination of former Lebanese prime minister Rafiq al-Hariri last year and the subsequent withdrawal of Syrian troops.
A UN investigation into al-Hariri's assassination has implicated Syria.
Tishrin said it was the first time Syria seized US-made weapons, and hinted the rifles had been brought in as an implicit US and Israeli threat to the country.
"As if it was meant to send an urgent message to the leadership and the people of Syria to realise the dangers of ... confronting projects that are hostile to Syria and the Arab nation," the newspaper said.
Syria's secular rulers have faced
Islamist challenge in the past
Security forces have had occasional shootouts with Muslim insurgents in the Syrian capital before. In previous clashes, the fighters tended to belong to the Jund al-Sham, or Soldiers of Syria, which was formed in Afghanistan by Syrian, Palestinian and Jordanian extremists with links to Abu Musab al-Zarqawi, the head of al-Qaeda in Iraq.
In March, Syrian security forces killed a Jund al-Sham commander, Mohammed Ali Nasif, and his bodyguard in a clash northwest of Damascus.
Religious leaders also condemned Friday's attack.
A top Syrian Muslim cleric, Sheikh Ahmed Hassoun, said that "he who stands against Syria's security is standing in the other trench; antagonising religion, people, honour, homeland and the whole nation".
Bishop John Ibrahim, the head of the Syrian Orthodox - a Christian sect - in the northern Aleppo province, also condemned the attacks. "The perpetrators are serving the enemies," he said.