Russia is sending a reconnaissance ship from its Black Sea fleet to the coast off Syria, Interfax news agency reported on Monday, as President Barack Obama's administration launched a full-scale lobbying effort to win congressional support for a military strike on Syria.

The spy ship left Russia's naval base in the Ukrainian Black Sea port of Sevastopol, late on Sunday, and is heading “to the appointed region of military service in the eastern Mediterranean,” an Interfax report quoting an unidentified military source said. The ship named SSV-201 Priazovye is on a mission "to gather current information in the area of the escalating conflict,” it added.

Russian defense ministry officials declined to comment on the development but, according to an Interfax report, the ship would operate separately from a naval fleet, which is already present in the Mediterranean, Reuters reported.

Meanwhile, Obama's administration has intensified its campaign to garner support from the U.S. Congress for a military strike on Syria. The president, on Saturday, had said that he would seek congressional consent before launching punitive military attacks against the Syrian government.

On Sunday, Secretary of State John Kerry said the U.S. has solid proof that the Syrian government used sarin gas -- a deadly chemical agent developed by Nazi scientists in 1938 -- in an attack on Aug. 21, which killed more than 1,400 people in Damascus.  

“Samples of hair and blood have been tested and they have reported positive for signatures of sarin,” Kerry said, Associated Press, or AP, reported.

“Each day that goes by, this case is even stronger. We know that the regime ordered this attack . . . We know where the rockets came from. We know where they landed. We know the damage that was done afterwards,” he added.

Obama also sought support from former foe, Sen. John McCain (R-Ariz.), and invited him to come to the White House to discuss the Syrian crisis.

In an attempt to seek international support, the U.S. reportedly shared evidence of the chemical attack with Russia and China, and spoke to diplomats in Arab countries by phone.

Israel, a key U.S. ally and a staunch supporter of military action against Syria, chose to remain silent over Obama’s decision to delay a military strike pending congressional approval. Israeli officials and ministers, who had been strongly advocating a U.S.-led military action against Syria, did not react to Obama’s retraction, reportedly after Prime Minister Benjamin Netanyahu, in a closed-door meeting, urged government officials not to comment on the issue.

Russia, a key ally of Bashar Assad's government, is against any kind of military action against the regime and has been countering the U.S.' move to strike Syria. Russian Foreign Minister Sergei Lavrov, on Monday, said that Russia is not convinced by the evidence presented by the U.S. of the alleged chemical attack.

"What we were shown before and most recently by our American partners as well as the British and the French absolutely does not convince us," Lavrov said at a university lecture in Moscow, AP reported.

President Vladimir Putin, on Saturday, had described U.S. claims about the chemical attack as “utter nonsense.”

According to a Sky News report, Lavrov, referring to the upcoming G-20 summit later this week, said:

"If the action announced by the US President - to the great regret of all of us - does in fact take place ... it will put off the chances of (holding) this conference for a long time, if not forever."