Russian riot police arrest 1,700 during rallies to support Alexei Navalny

April 22 (UPI) -- Close to 2,000 people have been arrested across Russia while marching to support jailed Kremlin critic Alexei Navalny, who is said to be seriously ill in the hospital.

Rallies were held across the country on Wednesday to pressure President Vladimir Putin to release Navalny, who was hospitalized after a three-week hunger strike. Navalny's doctor said he could die unless he receives proper medical care.

The demonstrations were held on the same day Putin said in his annual state of the nation address that any country that threatens Russia will regret it "in a way they've never regretted anything before."

More than 14,000 people protested in more than two dozen cities, including 6,000 at the largest event in Moscow, according to Russia's interior ministry. About 4,500 marched in St. Petersburg, The Moscow Times reported.

Other protests took place in Vladivostok in the Far East, a number of cities in Siberia, and the central city of Vladimir.

Officials said about 1,700 demonstrators were arrested on Wednesday.

The last time similar demonstrations were held in January and February, when more than 11,000 people were detained. Since then, the Kremlin has cracked down on human rights organizations, independent journalists and Navalny's associates. Navalny's activist network could be shuttered soon, according to independent rights monitors.

Authorities had warned against the protests and there was a heavy police presence in most major cities.

Russia's penitentiary system said Navalny was in "satisfactory" condition and has been examined by a doctor on a daily basis at the high-security prison east of Moscow. Officials added that Navalny, who's nearly three weeks into his hunger strike, was prescribed "vitamin therapy."

Supporters have vowed to continue their activities despite attempts by authorities to ban Navalny's organizations.

Russian prosecutors have asked a court to outlaw Navalny's Anti-Corruption Foundation and his regional network as "extremist" organizations. A Moscow court is scheduled to hand down the verdict next week.

Some Navalny allies have been arrested and convicted for participating in the January and February rallies. Others have fled Russia to avoid prosecution.

"When we announced the rally, we had a feeling that this is the end," Ivan Zhdanov, who heads the Anti-Corruption Foundation, said according to the Moscow Times. "But now the feeling is that we'll continue."

Despite falling short of their 500,000-protester goal, Volkov called the nationwide demonstrations a success.

Charles Michel, president of the European Council, tweeted Wednesday that arresting supporters is "deplorable."

"Authorities must respect the right to assembly," he wrote. "I urge that the necessary and quality medical care be granted to Alexei Navalny and that he be released from prison."

U.S. national security adviser Jake Sullivan said last weekend that the U.S. government would respond with consequences for Russia if Navalny dies. Putin and the Russian government have been heavily criticized for their efforts to silence the opposition leader and many believe they were behind Navalny's poisoning last summer.

State Department spokesman Ned Price tweeted that Moscow is responsible for Navalny's present condition and called on Russian officials to "allow him access to necessary medical care immediately."