KIEV, Nov. 29 (CGTN) -- The United States and Britain pledged their support for Ukraine amid its tensions with Russia around the Kerch Strait, local media reported on Thursday.

According to the Ukrainian government-run Ukrinform news agency, the U.S. Ambassador to Ukraine Marie Yovanovitch called for the de-escalation of the tensions and urged Russia to release captured Ukrainian sailors.

"The U.S. supports the right of Ukraine to defend its rights and we will continue to stand next to the Ukrainian people... And our support is not only verbal," Yovanovitch was quoted as saying during the 2nd International Maritime Security Conference in Kiev.

The British Ambassador to Ukraine Judith Gough, who also participated in the conference, said Britain condemns Russia's actions in the Kerch Strait and stands ready to assist Ukraine in boosting the capabilities of its navy.

"We will work for the development of the Ukrainian Navy," Gough told the conference.

On Sunday, three Ukrainian naval ships attempting to sail through the Kerch Strait from the Black Sea to the Sea of Azov were attacked and seized by Russian forces, which claimed that the ships violated the Russian border.

The Ukrainian Navy said that it had informed Russia in advance of the passage of its vessels through the strait, while Russia said it had received no such report and the ships ignored multiple warnings by the Russian border guards.

The General Staff of the Ukrainian Armed Forces said that more than 20 Ukrainians were detained during the tensions.

Ukraine has accused Russia of "aggressive actions" in the Azov Sea after Russia inaugurated a bridge over the Kerch Strait earlier this year and started inspecting commercial ships sailing through the sea and the strait.

Moscow rejected such accusations, saying Russia can exercise its sovereign rights in nearby waters off Crimea and the Kerch Strait is not an international passage.

Relations between Russia and Ukraine have been deteriorating since Crimea was incorporated into Russia in March 2014 following a local referendum, which was rejected by Ukraine and Western countries.