Interactive Grid: Keeping track of the conflict in Syria through videos, images and tweets.

The Syrian army’s March weapons request to its Russian supplier was the stuff of everyday battles in a long and grueling conflict. ­Twenty-thousand Kalashnikov assault rifles and 20 million rounds of ammunition. Machine guns. Grenade launchers and grenades. Sniper rifles with night-vision sights.

The Syrian army general asked for a price quote “in the shortest possible time.” He closed with kind regards to Rosoboronexport, Russia’s state arms exporter.

The flow of arms to Syria, including the advanced S-300 missile defense batteries that Moscow said this week it would supply, continues amid hopes that an international conference, jointly proposed by the United States and Russia, will lead to a negotiated political settlement of Syria’s civil war.

No date has been set for the conference, however, and it might not get off the ground until July, despite initial hopes that it would be held this month. Although Syria’s foreign minister said Wednesday that government representatives would attend “with every good intention,” opposition leaders are in a stalemate over who should represent them and whether they should even show up.

In the meantime, all sides are hedging their bets.

Britain and France will be free to arm the Syrian rebels, if they choose, when a European Union embargo they fought to lift expires Friday. The Obama administration, while still holding its fire, is poised to begin sending lethal aid to opposition forces. Qatar and Saudi Arabia, along with wealthy individuals in the Persian Gulf, have spent millions on weapons for favored rebel groups.

Iran has stepped up its supplies of technology, equipment and personnel to the Syrian government, and Lebanon-based Hezbollah — an Iranian and Syrian client — has started sending legions of fighters to the government side.

But no outside force has been as consistent in its involvement in Syria as Russia. Moscow has served as the primary arms supplier to the government of President Bashar al-Assad, as it did for the predecessor government run by his father.

Alexei Ventslovsky, foreign media projects manager for Rosoboronexport, said the company would have no comment on the March request from the Syrian government. But the document — a copy of which, in its original typed Cyrillic script, was obtained by The Washington Post — underlined the Russians’ commitment to supplying Syria as part of the “indefinite delivery, indefinite quantity” contracts that allow for repeated orders.

Such major military contracts are only one aspect of Russia’s interests in Syria, which include significant energy investments and a naval base in the Mediterranean port city of Tartus.

The United States and its pro-opposition partners have appealed to Russia to preserve such long-term interests in Syria by moving to the winning side and have been perplexed by the Russians’ resistance. President Obama has said that Assad must go, and legions of senior U.S. officials, citing humanitarian concerns, have argued that Russia should at least get out of the way.

Yet beneath the cooperative words of Foreign Minister Sergei Lavrov, who has met repeatedly with Secretary of State John F. Kerry in recent weeks to plan the conference, many Russia experts say the United States has misread Russia’s mind-set and goals.

Russian policy “is not insane or irrational from [Russia’s] point of view,” said Fiona Hill, a senior foreign policy fellow at the Brookings Institution. “They’re just waiting to see how it plays out.”

The Russians, Hill and other experts said, see the United States as the irrational player in the region, upsetting the status quo and adding fuel to sectarian conflicts in Russia’s own neighborhood. Recent territorial gains by Assad’s forces — and the Americans’ reluctance to supply their own arms — have only hardened the Russians’ resolve.

“They’re certainly serious about having a conference,” Hill said, but more for the purpose of “preventing any kind of unilateral action” by the United States than thinking that it will bring results.

Russian President Vladmir Putin “has based a fair bit of his domestic legitimacy on the idea that Russia goes its own way and does not take orders from the West, has its own friends and makes its own choices internationally, ” said Stephen Sestanovich, the George F. Kennan Senior Fellow for Russian and Eurasian Studies at the Council on Foreign Relations.

“Judged by almost any imaginable criteria,” he said, “Syria seems like a pretty good friend of Russia.”

At the same time, diplomats and analysts said Russia is making subtle efforts to reassert itself in the Middle East and is putting out the word that it plans to vigorously defend its interests.

Early this month, institutes backed by the Russian government hosted a conference in the Moroccan city of Marrakesh, inviting more than a hundred of the region’s most influential newspaper columnists, pundits and policy experts. In attendance were officials from Persian Gulf Arab states staunchly opposed to Russia’s support for Syria as well as representatives of Hezbollah and Gaza’s Hamas organization. The two-day conference was billed as a forum on political Islam, but a recurring theme was Russia’s new assertiveness in the region, attendees said in interviews.

“The Russians’ real intention seemed to be to say, ‘We’re back,’ ” said one Arab analyst who attended the event but who requested anonymity in order to speak frankly about sensitive discussions with the conference’s Russian hosts.

“They were adamant in saying they would continue to back Assad,” the analyst said.

Raghida Dergham, a Lebanese newspaper columnist who also attended the forum, said she was struck by the nationalist notes sounded by several of the Russian speakers and hosts, whom she described as unapologetic about Moscow’s backing not only for the repressive government in Damascus but in Tehran as well. At the same time, the Russians seemed eager to engage Muslim Brotherhood leaders in Egypt and Gaza, despite worries about a growing Islamist problem at home, she wrote in a blog.

“The broad headline appeared to be that Russia was turning a new leaf, tempering in appearance the tone of its ‘no’ to the rise of Islamic power, while insisting in effect on absolutely refusing to allow them to come to power in Damascus,” Dergham wrote. “As for the stance on Syria, it was identical across the spectrum of Russian opinions, being, in short, one of complete support for Russia’s role in its political, military and diplomatic aspects.”

The same message is being conveyed through diplomatic channels in Arab capitals, including in Sunni-Arab majority states that are actively supporting the Syria rebels, according to Middle East diplomats and senior policy analysts based in the region. Moscow has repeatedly torpedoed U.N. resolutions intended to punish Assad, and earlier this month, it blocked Syria’s southern neighbor, Jordan, from formally requesting a U.N. Security Council inspection of Syrian refugee camps along its northern border. Lavrov said the inspections could become a pretext for “foreign intervention” in the Syrian conflict.

Some Middle East diplomats and experts expressed concern about what one described as a “new Cold War” in the region, with Washington and Moscow backing opposing sides in an endless series of proxy battles. Moustafa Alani, director of national security and terrorism studies at the Gulf Research Center, an influential think tank in Dubai, said Russia appears to be challenging what until recently was conventional wisdom in the region: that Russia has lost influence in the region by backing the losing sides in the Arab Spring revolts.

“The Russians have a different calculation,” Alani said. “They think they still have plenty of support in the Middle East, and they’re protecting what they see as their interest. The very clear message is, ‘Don’t count us out.’ ”

Putin’s government has said it will sign no new contracts with Assad, but will continue deliveries under previous deals, including the S-300 order. In a clear reference to the E.U. decision, and warnings from Israel about the 200- to 300-mile range of the missiles, Russian Deputy Defense Minister Sergei Ryabkov said the delivery might actually calm things down in Syria.

“We believe that such steps to a large extent help restrain some ‘hotheads’ considering a scenario to give an international dimension to this conflict,” Ryabkov said.

Natasha Abbakumova in Moscow contributed to this report.