Axios

The State Department issued an increased travel warning Thursday advising U.S. citizens considering travel to China to "exercise increased caution" due to "arbitrary enforcement of local laws."

Background: China has arrested two Canadian citizens in the last month for allegedly endangering Chinese security, though experts tell Axios they were likely detained as a retaliatory measure for Canada's arrest of Huawei CFO Meng Wanzhou. In December, the State Department also issued an increased travel warning for Russia — where an American citizen is currently being held on charges of espionage — due to risk of "terrorism, harassment, and the arbitrary enforcement of local laws."

Go deeper: A new era of hostility in the U.S.-China fight

Russian news agency Interfax said that Russian authorities formally brought espionage charges against American citizen Paul Whelan on Thursday, per the New York Times.

The backdrop: Whelan, a former U.S. Marine, was arrested in Moscow last Friday and could face up to 20 years in prison if found guilty. Intelligence experts believe he may have been detained as retribution for the arrest of confessed Russian agent Maria Butina. Whelan pleaded not guilty to espionage charges, according to his lawyer.

Go deeper: American detained in Russia visited by U.S. ambassador

Paul Whelan, the American citizen arrested in Moscow last Friday on charges of espionage, was visited by U.S. Ambassador to Russia Jon Huntsman on Wednesday, NBC News reports.

Why it matters: It's unusual for such a high-ranking official to make this kind of visit, according to national security analyst Evelyn Farkas. Whelan is facing up to 20 years in prison if found guilty. Some intelligence experts believe he was detained as retribution for the arrest of confessed Russian agent Maria Butina.

Israeli Prime Minister Benjamin Netanyahu is helping to open doors in Washington for Honduran President Juan Orlando Hernández as part of his effort to push the Latin American nation to move its embassy in Israel to Jerusalem. Israeli officials said this was one of the reasons Netanyahu organized a trilateral meeting with Hernández and Secretary of State Mike Pompeo Tuesday in Brasilia on the sidelines of Brazilian President Jair Bolsonaro's inauguration.

Why it matters: U.S.-Honduran relations are currently tense over immigration issues, specifically migrant caravans. President Trump even threatened to cut U.S. aid to Honduras and other Central American countries if they do not stop their migrant flows to the U.S. Israeli officials said that Honduras had requested Israel's help in warming relations with the Trump administration as one of its conditions for moving its embassy to Jerusalem.

During their meeting in Brasilia on Tuesday, Secretary of State Mike Pompeo and Israeli Prime Minister Benjamin Netanyahu failed to make a deal regarding the Trump administration's objections to a proposed $500 million deal for F-16 jets between Israel and Croatia, a senior Israeli official told reporters.

Why it matters: Croatian Prime Minister Andrej Plenković said earlier this week that he was waiting for the outcome of the Pompeo-Netanyahu meeting and threatened to cancel the deal if Israel and the U.S. could not resolve their differences. The deal was supposed to be implemented before the end of 2018, but has been held up by the U.S. for almost two months.