Russian Foreign Minister Sergei Lavrov said Monday the evidence provided by the United States on the alleged use of chemical weapons by the Syrian army was not solid and had not convinced Moscow to change its position on military intervention in the Arab country, the Interfax news agency reported.

"Yes, they showed us some reports that did not contain anything concrete - no geographic coordinates or the names or evidence that the samples were collected by professionals," Lavrov said during an appearance at the International Relations Institute in Moscow.

The reports make no mention of the fact that numerous experts have raised doubts about the videos posted on the Internet of the chemical attack, Lavrov said.

"What our American, British and French partners have shown us recently also does not convince us at all," the Russian foreign minister said.

The Russian Black Sea Fleet's Priazovie, an exploration vessel, sailed from Sevastopol on Sunday night for the Syrian coast to gather information on the situation, Interfax reported, citing officials.

Over the weekend, U.S. officials stepped up the campaign to sway public opinion in favor of a military strike on Syria.

Secretary of State John Kerry said Sunday the United States had evidence that Syria's government used the nerve agent sarin in an Aug. 21 attack on the outskirts of Damascus.

Hair and blood samples from victims of the attack have "tested positive for signatures of sarin," Kerry said in a series of interviews with U.S. television networks.

The attack killed 1,429 people, U.S. officials say.

President President Bashar Assad, meanwhile, said Sunday that Syria would continue its "fight against terrorism" despite threats of military action by the United States.

U.S. President Barack Obama said Saturday he had decided on "military action" against Syria but would seek congressional approval first.

Obama gave no specific date for the strike, saying it would occur when Washington decides.

Congress is currently on summer recess, but is scheduled to return to session on Sept. 9.

The U.S. government released a report Friday stating that a chemical weapons attack was staged on Aug. 21 in Ghouta that killed 1,429 people, including 426 children.

U.N. inspectors in Syria to investigate the Aug. 21 incident and other alleged chemical weapons attacks left the country Saturday.

Britain's House of Commons voted 285-272 last week against a motion that would have opened the door to that country's participation in a U.S.-led strike, but France said it remained "prepared" to participate in a punitive action against Syria.

More than 92,000 people died in Syria's internal conflict between March 2011 and April 2013, according to a report released in June by the U.N. Office of the High Commissioner for Human Rights. EFE