Palestinians militants from various armed factions, including Hamas, attend a news conference in Gaza City June 17, 2014. REUTERS/Mohammed Salem Exclusive: Hamas has paid North Korea for missiles and communications equipment in arms deal worth hundreds of thousands of dollars

Hamas militants are attempting to negotiate a new arms deal with North Korea for missiles and communications equipment that will allow them to maintain their offensive against Israel, according to Western security sources.

Security officials say the deal between Hamas and North Korea is worth hundreds of thousands of dollars and is being handled by a Lebanese-based trading company with close ties to the militant Palestinian organisation based in east Beirut.

Hamas officials are believed to have already made an initial cash down payment to secure the deal, and are now hoping that North Korea will soon begin shipping extra supplies of weapons to Gaza.

“Hamas is looking for ways to replenish its stocks of missiles because of the large numbers it has fired at Israel in recent weeks,” explained a security official. “North Korea is an obvious place to seek supplies because Pyongyang already has close ties with a number of militant Islamist groups in the Middle East.”

Using intermediaries based in Lebanon, Hamas officials are said to be intensifying their efforts to sign a new agreement with Pyongyang to provide hundreds of missiles together with communications equipment that will improve the ability of Hamas fighters to coordinate operations against Israeli forces.

Like other Islamist terror groups in the region such as Hizbollah, Hamas has forged close links with North Korea, which is keen to support groups that are opposed to Western interests in the region.

The relationship between Hamas and North Korea first became public in 2009 when 35 tons of arms, including surface-to-surface rockets and rocket-propelled grenades, were seized after a cargo plane carrying the equipment was forced to make an emergency landing at Bangkok airport. Investigators later confirmed that the arms cache has been destined for Iran, which then planned to smuggle the weapons to Hizbollah in Lebanon and Hamas in Gaza.

Following Israel’s latest military offensive against Hamas operatives based in Gaza, Western security officials say Hamas is now trying to persuade North Korea to provide fresh supplies of rockets to replace the thousands of missiles that have been fired at Israel since the commencement of hostilities two weeks ago.

Israeli military commanders supervising operations against Gaza believe North Korean experts have given Hamas advice on building the extensive network of tunnels in Gaza that has enabled fighters to move weapons without detection by Israeli drones, which maintain a constant monitoring operation over Gaza.

The North Koreans have one of the world’s most sophisticated network of tunnels running beneath the demilitarised zone with South Korea, and Israeli commanders believe Hamas has used this expertise to improve their own tunnel network.

The Hamas arsenal has become increasing sophisticated with foreign assistance and now boasts five variants of rockets and missiles. Its basic weapon is the Iranian-designed Qassam rocket with a range of less than ten miles but it also has a large stockpile of the 122mm Katyushas which boast a range of up to 30 miles.

The introduction of the M-75 and Syrian-made M0302 missiles means Hamas boast offensive weapons with a longer range of up to 100 miles and a much greater explosive impact.

Since the 2012 eight-day war, Hamas has increased the size and strength of its rocket arsenal. Israeli military intelligence puts its stockpile at around 10,000 rockets and mortars, including long-range rockets capable of reaching Jerusalem, Tel Aviv and the northern port city of Haifa.