For the second time in a week, a Russian fighter jet flew up close to a U.S. Navy reconnaissance plane in the Black Sea, a U.S. official tells Fox News.

This latest incident occurred about 30 miles from Russia in a northern portion of the Black Sea about 100 miles from Russian-held Crimea.

The two incidents occurred before and after Russian Foreign Minister Sergey Lavrov's visit to Washington and Alaska this week.

The latest incident occurred Friday morning, when another Russian Su-27 jet flew 40 feet from a U.S. Navy P-8 Poseidon recon plane flying in international airspace, according to U.S. officials.

A previous incident on Tuesday involved an armed Russian Su-27 jet flying within 20 feet of the U.S. reconnaissance plane

It is not immediately clear if the Russian fighter jet on Friday was armed or whether the same American and Russian jets were involved in this latest episode.

The Friday Russian intercept comes a day after Fox News first reported an armed Russian fighter jet with six air-to-air missiles under its wings came "dangerously close" to US Navy recon plane off the coast of Crimea, according to U.S. officials.

Fox News has since learned the Russian missiles were medium-range AA-10 air-to-air missiles, which NATO calls "Alamo."

The Pentagon has stepped up its reconnaissance flights in the Black Sea since 2014 when Russian annexed Crimea under the guise of a military training exercise. The U.S. Navy has also sent more warships to the region.

In February, Russian jets buzzed a U.S. Navy destroyer in the Black Sea. Last month, that same warship - USS Porter -- launched cruise missiles into Syria from the Mediterranean.

The US Army has deployed dozens of battle tanks and hundreds of soldiers to conduct joint training exercises in Romania along the Black Sea since first arriving in a February. More NATO exercises are expected in the region in the coming months.

On Thursday, Defense Secretary Jim Mattis visited Lithuania to reassure anxious Baltic NATO allies on Russia's doorstep.

In addition to the two incidents in the Black Sea, on Thursday, a Russian Su-24 attack jet flew south from eastern Russia into South Korea's air defense zone, forcing Seoul to scramble two F-16 fighter jets. More concerning to the Pentagon, the Russian jet flew 70 miles from the USS Carl Vinson aircraft carrier in the Sea of Japan.

Also on Thursday, a new shipment of Russian SA-21 surface-to-air missiles arrived in Syria, doubling the number of missiles the Russians have there, less than a week after pushing forward a new ceasefire agreement in Syria along with Iran and NATO-ally Turkey. While the U.S. government had a representative at the Syrian peace talks in Astana, Kazakhstan, the United States was not a party to the agreement.

President Trump's national security advisor H.R. McMaster told White House reporters Friday the United States would continue to "confront" Russia going forward.

“What the president has made clear is that he will confront Russia’s disruptive behavior, such as the support for the murderous Assad regime in Syria … its enabling of Iran, and it’s very destructive policy and strategy that it’s executing across the Middle East."

But McMaster also said the Trump administration would explore areas where the two nations could potentially cooperate.

Russia "could best advance its interests from cooperating with the United States and others to resolve those conflicts rather than perpetuate them," McMaster said.