Damage to submarine cables in the Red Sea is disrupting telecommunications networks and forcing providers to reroute as much as a quarter of traffic between Asia, Europe and the Middle East, including internet traffic.

Cables belonging to four major telecoms networks have been “cut” causing “significant” disruption to communications networks in the Middle East, according to Hong Kong telecoms company HGC Global Communications, CNN reported.

HGC estimates that 25% of traffic between Asia and Europe as well the Middle East has been impacted, it said in a statement Monday.

The company said it is rerouting traffic to minimize disruption for customers and also “extending assistance to affected businesses.”

HGC did not say how the cables had been damaged or who was responsible.

Underwater cables are the invisible force driving the internet, with many funded in recent years by internet giants such as Google, Microsoft, Amazon and Facebook parent Meta. Damage to these subsea networks can cause widespread internet outages, as happened following the Taiwan earthquake in 2006.

The destruction of cables in the Red Sea comes weeks after the official Yemeni government warned of the possibility that Houthi rebels would target the cables. The Iranian-backed militants have already disrupted global supply chains by attacking commercial vessels in the crucial waterway.

Reports last week from Israeli news outlet Globes suggested the Houthis had been behind the damage to the cables. Yemeni rebel leader Abdel Malek al-Houthi denied the allegations. “We have no intention of targeting sea cables providing internet to countries in the region,” he said.

Yemen’s government has since blamed British and US military units operating in the area for the damage, according to a report Saturday by the country’s state news agency. CNN has contacted the UK and US governments for comment but was unable to immediately contact the Yemeni government.

In a statement last week, the Yemeni government stressed the importance of protecting the undersea cables and said it was “keen also to provide all necessary facilities to get such submarine cables repaired and maintained.”

Among the networks affected is Asia-Africa-Europe 1, a 25,000-kilometer (15,534-mile) cable system connecting South East Asia to Europe via Egypt. The Europe India Gateway (EIG) has also been damaged.

EIG connects Europe, the Middle East and India and counts Vodafone as a major investor. Vodafone, a large mobile network operator in the United Kingdom, declined to comment.

The company says on its website that it can send internet traffic across some 80 submarine cable systems that reach 100 countries.

Most large telecoms companies rely on multiple undersea cable systems, allowing them to reroute traffic in the event of an outage to ensure uninterrupted service.